This is a list of lakes in Wales. Most lakes in Wales start with the word "Llyn", which is Welsh

Welsh language

Welsh is a member of the Brythonic branch of the Celtic languages spoken natively in Wales, by some along the Welsh border in England, and in Y Wladfa...

 for "Lake".

By area

In terms of surface area, the ten largest lakes in Wales are

• Llyn Tegid (Bala Lake) — 1196 acres (4.8 km²)
• Llyn Trawsfynydd
  Llyn Trawsfynydd
  Llyn Trawsfynydd is a large man-made reservoir situated near the village of Trawsfynydd in Gwynedd, North Wales. With a total surface area of 4.8 km² the reservoir is slightly more extensive than Wales's largest natural lake, Llyn Tegid .Originally created in 1928 as the header reservoir for...
  
   — 1180 acres (4.8 km²)
• Lake Vyrnwy
  Lake Vyrnwy
  Lake Vyrnwy Nature Reserve and Estate is an area of land in Montgomeryshire, Powys, Wales, surrounding the Victorian reservoir of Lake Vyrnwy. Its stone-built dam, built in the 1880s, was the first of its kind in the world. The Nature Reserve and the area around it are jointly managed by the Royal...
  
   — 1120 acres (4.5 km²)
• Llyn Brenig
  Llyn Brenig
  Llyn Brenig is a reservoir located in North Wales, in the heart of the Denbigh Moors, on the border between the counties of Conwy and Denbighshire...
  
   — 894 acres (3.6 km²)
• Llyn Celyn
  Llyn Celyn
  Llyn Celyn is a large reservoir constructed between 1960 and 1965 in the valley of the River Tryweryn in Gwynedd, North Wales. It measures roughly 2½ miles long by a mile wide, and has a maximum depth of...
  
   — 800 acres (3.2 km²)
• Llyn Alaw
  Llyn Alaw
  Llyn Alaw is a man-made reservoir on Anglesey, North Wales. It is used to supply drinking water to the northern half of the island and does so at a rate of 35 million litres a day. It was created in 1966 on existing marshland....
  
   — 762 acres (3.1 km²)
• Claerwen Reservoir — 655 acres (2.7 km²)
• Llyn Clywedog — 601 acres (2.4 km²)
• Nant y Moch Reservoir
  Nant y Moch
  Nant-y-moch Reservoir is situated in the Cambrian Mountains in northern Ceredigion, Wales. The reservoir which flooded a part of the valley of the River Rheidol and its headwaters derives its name from a stream, the Nant-y-moch , which formerly flowed into the River Rheidol at this spot. The dam...
  
   — 525 acres (2.1 km²)
• Caban Coch Reservoir — 519 acres (2.1 km²)

All of the above, with the exception of Llyn Tegid, are reservoirs held back by dams. Llyn Tegid was the largest natural lake in Wales though its level is now artificially controlled. The largest natural lake in South Wales

South Wales

South Wales is an area of Wales bordered by England and the Bristol Channel to the east and south, and Mid Wales and West Wales to the north and west. The most densely populated region in the south-west of the United Kingdom, it is home to around 2.1 million people and includes the capital city of...

 is Llangors Lake

Llangorse Lake

Llangorse Lake is the largest natural lake in south Wales, and is situated in the Brecon Beacons National Park, near to the town of Brecon and the village of Llangors....

 or Llyn Syfaddan.

By unitary authority

This list of Welsh lakes ordered by unitary authority

Unitary authority

A unitary authority is a type of local authority that has a single tier and is responsible for all local government functions within its area or performs additional functions which elsewhere in the relevant country are usually performed by national government or a higher level of sub-national...

 includes lakes with a surface area of greater than 5 acres (2 ha), but excludes those lakes and ponds created as part of an active industrial site (i.e, works ponds) and also excludes service reservoirs used to store drinking water as part of the water supply system. Grid references identify the approximate centre of the lake or the dam in the case of artificial reservoirs. For some lakes, the unitary authority boundary passes through a lake. In these case the lake is represented in the list for each appropriate authority. Known occurrences include Llyn Brenig

Llyn Brenig

Llyn Brenig is a reservoir located in North Wales, in the heart of the Denbigh Moors, on the border between the counties of Conwy and Denbighshire...

, Pontsticill Reservoir

Pontsticill Reservoir

Pontsticill Reservoir or Taf Fechan Reservoir is a large reservoir on the Taf Fechan lying partly in the county of Powys and partly within the county borough of Merthyr Tydfil in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark...

, Llwyn-on Reservoir

Llwyn-On Reservoir

Llwyn-on Reservoir is the largest and southernmost of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park. The eastern half is in the Merthyr Tydfil unitary authority area and the western half is in the Rhondda...

, Cantref Reservoir

Cantref Reservoir

Cantref Reservoir is the middle of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park, mostly in the Powys unitary authority area and within the historic county boundaries of Breconshire...

 and Dol y Gaer Reservoir. All occurrences are marked with an asterisk (*).

Anglesey

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llyn Alaw Llyn Alaw Llyn Alaw is a man-made reservoir on Anglesey, North Wales. It is used to supply drinking water to the northern half of the island and does so at a rate of 35 million litres a day. It was created in 1966 on existing marshland....	River Alaw		762	Water supply to north Anglesey Anglesey Anglesey , also known by its Welsh name Ynys Môn , is an island and, as Isle of Anglesey, a county off the north west coast of Wales...
Llyn Bodgylched	No main catchment
Llyn Cefni Llyn Cefni Llyn Cefni is a small reservoir in the centre of Anglesey, Wales which is managed by Welsh Water and Hamdden Ltd. It is located just one kilometre north of the island's county town of Llangefni and is the source of the Afon Cefni and other smaller watercourses...	Afon Cefni Afon Cefni Afon Cefni is one of the major rivers on the island of Anglesey, Wales. It is long. The river starts at the Llyn Cefni in the centre of the island and then runs south through the county town of Llangefni. Just north of the A55 the river turns and flows south-west. It passes through the flatlands...		167	Water supply to central Anglesey
Llyn Coron	No main catchment		69
Llyn Dinam	No main catchment		24
Llyn y Gors	No main catchment			Amenity (fishing)
Llyn Gwaith-glo	No main catchment
Llyn Llygeirian	No main catchment
Llyn Llywenan Llyn Llywenan Llyn Llywenan is a lake in western Anglesey, Wales found just over north of the village of Bodedern and east of the town of Holyhead. At a maximum length of and breath of it has a surface area of only...	No main catchment
Llyn Llwydiarth	Afon Braint
Llyn Maelog	No main catchment		65	Former water supply to Rhosneigr
Llyn Pen y Parc	No main catchment			Water supply (disused)
Llyn Penrhyn	No main catchment		55	RSPB bird reserve
Llyn Rhosddu	No main catchment
Llyn Traffwll	No main catchment		91
Llyn Treflesg	No main catchment			RSPB bird reserve

Blaenau Gwent

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Carno Reservoir	Ebbw River Ebbw River The Ebbw River is a river in South Wales.The main Ebbw River is formed by the confluence of the two minor Ebbw rivers, Ebbw Fach, and Ebbw Fawr ....			reservoir
Cwmtillery Reservoir	Ebbw River Ebbw River The Ebbw River is a river in South Wales.The main Ebbw River is formed by the confluence of the two minor Ebbw rivers, Ebbw Fach, and Ebbw Fawr ....			reservoir
Rhyd-y-blew Pond	Ebbw River Ebbw River The Ebbw River is a river in South Wales.The main Ebbw River is formed by the confluence of the two minor Ebbw rivers, Ebbw Fach, and Ebbw Fawr ....
Parc Brynbach lake	Sirhowy River			amenity
Scotch Pete's Reservoir	Sirhowy River			reservoir
Shon-Sheffrey's Reservoir	Sirhowy River			reservoir

Bridgend

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Kenfig Pool Kenfig Pool Kenfig Pool is a National Nature Reserve situated near Porthcawl, Bridgend. Wild storms and huge tides between the 13th and 15th centuries are mainly responsible for creating the Kenfig dunes near Porthcawl, as they threw vast quantities of sand up over the Glamorgan coast. This buried the nearby...	River Kenfig River Kenfig The River Kenfig is a small river in south Wales, straddling the county boroughs of Neath Port Talbot and Bridgend. It is approximately 11 miles/18 kilometres long.-Course:...		70	Natural lake

Caerphilly

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Lower Blaen Rhymney Reservoir	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			reservoir
Upper Blaen Rhymney Reservoir	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			reservoir
Bute Town Reservoir	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...
Nant-y-draenog Reservoir	Sirhowy River		5	reservoir
Parc Cwm Darran Lake	Rhmney River			amenity
Rhaslas Pond	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...
Ffrwd Farm lake (west)	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			angling
Ffrwd Farm lake (east)	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			angling

Cardiff

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Cardiff Bay Cardiff Bay Cardiff Bay is the area created by the Cardiff Barrage in South Cardiff, the capital of Wales. The regeneration of Cardiff Bay is now widely regarded as one of the most successful regeneration projects in the United Kingdom. The Bay is supplied by two rivers to form a freshwater lake round the...	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Amenity
Llanishen Reservoir Llanishen Reservoir Llanishen Reservoir is a Victorian reservoir in North Cardiff in South Wales. The reservoir is one of the reservoirs constructed as part of the Taff Fawr scheme for supplying water to Cardiff and was completed in 1886...	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			Water supply to Cardiff Cardiff Cardiff is the capital, largest city and most populous county of Wales and the 10th largest city in the United Kingdom. The city is Wales' chief commercial centre, the base for most national cultural and sporting institutions, the Welsh national media, and the seat of the National Assembly for...
Lisvane Reservoir Lisvane Reservoir Lisvane Reservoir is a Site of Special Scientific Interest in Lisvane, Cardiff, south Wales.The reservoir is one of the reservoirs constructed as part of the Taff Fawr scheme for supplying water to Cardiff, completed in 1886...	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			Water Supply to Cardiff
Roath lake	Rhymney River Rhymney River The Rhymney River is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.-Path of the river:...			Recreation and amenity

Carmarthenshire

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llyn Brianne Llyn Brianne Llyn Brianne is a man-made lake or reservoir in the headwaters of the River Tywi in central Wales.-Construction:The reservoir was constructed by Wimpey Construction in the late 1960s and early 1970s in order to regulate the flow in the River Tywi to support large potable water abstraction at...	River Tywi River Tywi With a total length of the River Towy is the longest river flowing entirely within Wales, and is noted for its sea trout and salmon fishing.The river rises within of the Teifi on the lower slopes of Crug Gynan in the Cambrian Mountains and, flowing through the Towy Forest, forms the border...		530	Regulation reservoir
Garn Ffrwd pond?	Gwendraeth Fach		5
Llanelli North Dock lake	coastal water body			amenity (former dock)
Llyn Llech Owen Reservoir	Gwendraeth Fawr			amenity/reservoir
Cwm Lliedi Reservoir	Afon Lliedi			ex water supply
Llyn y Fan Fach Llyn y Fan Fach Llyn y Fan Fach is a dammed lake in the eastern border of the Black Mountain in Carmarthenshire, south Wales. Near to it is found Llyn y Fan Fawr.-Legend of Llyn y Fan Fach:...	River Tywi River Tywi With a total length of the River Towy is the longest river flowing entirely within Wales, and is noted for its sea trout and salmon fishing.The river rises within of the Teifi on the lower slopes of Crug Gynan in the Cambrian Mountains and, flowing through the Towy Forest, forms the border...
Llyn Taliaris	Afon Dulais
Lower Talley Lake	Afon Cothi			natural lake
National Wetlands Centre	coastal water bodies			conservation/wildlife
Old Castle Pond/Pond Twym	coastal lake			amenity
Sandy Water	coastal lake			amenity
Upper Lliedi Reservoir	Afon Lliedi			reservoir
Upper Talley Lake	Afon Cothi			natural lake
Usk Reservoir Usk Reservoir The Usk Reservoir is located in the upper Usk Valley, at above sea level, in Carmarthenshire, south Wales.The reservoir is situated in part of the Brecon Beacons National Park.Completed in 1955, it now covers some of land...	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...			Water supply
un-named lake	coastal lake			amenity

Ceredigion

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llyn Berwyn	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...		40	Natural lake
Llyn Craigpistyll	River Dyfi River Dyfi The River Dyfi is a river in Mid Wales. The Dyfi estuary forms the border between the counties of Gwynedd and Ceredigion.- Source :...			Natural lake
Dinas Reservoir	River Rheidol			Hydrolectricity
Llyn Du	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...			Natural lake
Llyn Egnant	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...			Water supply
Falcondale Lake Falcondale Lake Falcondale Lake is a Site of Special Scientific Interest in Ceredigion, west Wales....	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...			Amenity
Llyn Frongoch	River Ystwyth River Ystwyth The River Ystwyth is a river in the county of Ceredigion, Wales. Its source is a number of streams that include the Afon Diliw, located on the border of Ceredigion and Powys in the Cambrian Mountains....			Lead mining ?/ Natural
Llyn Fyrddon Fach	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...			Natural lake
Llyn Fyrddon Fawr	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...			Natural lake
Llyn Glandwgan	River Ystwyth River Ystwyth The River Ystwyth is a river in the county of Ceredigion, Wales. Its source is a number of streams that include the Afon Diliw, located on the border of Ceredigion and Powys in the Cambrian Mountains....			Natural lake
Glanmerin Lake	River Dyfi River Dyfi The River Dyfi is a river in Mid Wales. The Dyfi estuary forms the border between the counties of Gwynedd and Ceredigion.- Source :...			Natural lake
Llyn y Gorlan	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...			Water supply
Llyn Gwngi	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...			Natural lake
Llyn Hir	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...			Water supply
Nant-y-moch Reservoir Nant-y-moch Reservoir Nant-y-moch Reservoir is situated in the Cambrian Mountains in northern Ceredigion, Wales. The reservoir which flooded a part of the valley of the River Rheidol and its headwaters derives its name from a stream, the Nant-y-moch , which formerly flowed into the River Rheidol at this spot. The dam...	River Rheidol			Hydroelectricity
Llyn Rhosrhydd	River Ystwyth River Ystwyth The River Ystwyth is a river in the county of Ceredigion, Wales. Its source is a number of streams that include the Afon Diliw, located on the border of Ceredigion and Powys in the Cambrian Mountains....			Natural lake
Llyn Syfydrin	River Rheidol			Natural lake
Llyn Teifi	River Teifi River Teifi The River Teifi forms the boundary between the counties of Ceredigion and Carmarthenshire in south-west Wales for most of its 75 mile length, flowing into the sea below the town of Cardigan. The catchment of the river is estimated to be 1,008 square kilometres yielding an average flow at Glan...			Water supply

Conwy

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Aled Isaf Reservoir	River Clwyd River Clwyd The River Clwyd is a river in North Wales which rises in the Clocaenog Forest northwest of Corwen.It flows due south until at Melin-y-Wig it veers northeastwards, tracking the A494 to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd...		65.7	Water supply
Llyn Aled	River Clwyd River Clwyd The River Clwyd is a river in North Wales which rises in the Clocaenog Forest northwest of Corwen.It flows due south until at Melin-y-Wig it veers northeastwards, tracking the A494 to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd...		112.7	Water supply
Llyn Alwen Llyn Alwen Llyn Alwen is a small upland lake on the Denbigh moors in North Wales at SH 898 565.It lies on the rolling Silurian moorland to the north-west of Mwdwl-eithin and about 10 km to the east of Betws y Coed. The discharge from the lake flows under the A543 road to form the headwater of Alwen...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		65
Alwen Reservoir Alwen Reservoir The Alwen Reservoir or Cronfa Alwen is a 5km long reservoir near Pentre-Llyn-Cymmer in the county borough of Conwy, North Wales, held back by the 27 metre high Alwen Dam. It impounds the Afon Alwen, and the dam is 8km downstream from Llyn Alwen. It was built between 1909 and 1921, originally to...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		372.9	Water supply
Llyn Bochlwyd	River Ogwen River Ogwen The Afon Ogwen is a river in north-west Wales draining from some of the greatest peaks in Snowdonia before discharging to the sea on the eastern side of Bangor, Gwynedd.- Source :...		10
Llyn Bodgynydd Llyn Bodgynydd Llyn Bodgynydd is a lake in the Gwydir Forest in North Wales. It covers an area of some , and lies at a height of 822'.It is locally known as "Llyn Bod", or "Bod Mawr" , distinguishing it from a nearby, but much smaller lake to the north-east...			14	Industrial supply (disused)
Llyn Brenig Llyn Brenig Llyn Brenig is a reservoir located in North Wales, in the heart of the Denbigh Moors, on the border between the counties of Conwy and Denbighshire...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		920	Flow regulation
Llyn Coedty	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		11.6	Hydroelectricity
Llyn Conwy Llyn Conwy Llyn Conwy is a lake in the county of Conwy in central north Wales. It is the source of the River Conwy which, on flowing south out of the lake, swings round to then generally flow in a northerly direction for a distance of some to its discharge in Conwy Bay...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		101.3	Water supply for Llanrwst Llanrwst Llanrwst is a small town and community on the A470 road and the River Conwy in Conwy County Borough, Wales. It takes its name from the 5th century to 6th century Saint Grwst, and the original parish church in Cae Llan was replaced by the 12th-century church....
Llyn Cowlyd Llyn Cowlyd Llyn Cowlyd is the deepest lake in North Wales. It lies in the Snowdonia National Park on the edge of the Carneddau range of mountains, at a height of above sea level. The lake is long and narrow, measuring nearly long and about a third of a mile wide, and covers an area of...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		269	Water supply for Conwy Conwy Conwy is a walled market town and community in Conwy County Borough on the north coast of Wales. The town, which faces Deganwy across the River Conwy, formerly lay in Gwynedd and prior to that in Caernarfonshire. Conwy has a population of 14,208...
Llyn Crafnant Llyn Crafnant Llyn Crafnant is a lake that lies in a beautiful valley in North Wales where the northern edge of the Gwydir Forest meets the lower slopes of the Carneddau mountains and, more specifically, the ridge of Cefn Cyfarwydd. The head of the valley offers a profile of crags which are silhouetted at...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		52	Former water supply for Trefriw Trefriw Trefriw is a village in Conwy County Borough, Wales. It lies on the river Conwy in North Wales, a few miles south of the site of the Roman fort of Canovium, sited at Caerhun. The parish population in 2001 was 924....
Dulyn Reservoir Llyn Dulyn Llyn Dulyn is a lake on the edge of the Carneddau range of mountains in Snowdonia, North Wales.The lake covers an area of only , yet is extremely deep - it reaches to a depth of 189'...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		33	Water supply
Llyn Eigiau Llyn Eigiau Llyn Eigiau is a lake on the edge of the Carneddau range of mountains in Snowdonia, North Wales.The name Eigiau is thought to refer to the shoals of fish which once lived here. Early maps refer to it as Llynyga...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		120
Llyn Elsi Llyn Elsi Llyn Elsi is a lake located above the village of Betws-y-coed in the Snowdonia National Park in North Wales. It is a reservoir providing water for the village....	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		26	Water supply for Betws-y-coed Betws-y-Coed Betws-y-Coed is a village and community in the Conwy valley in Conwy County Borough, Wales. It has a population of 534. The name Betws or Bettws is generally thought to be derived from the Anglo-Saxon Old English 'bed-hus' - i.e. a bead-house - a house of prayer, or oratory...
Llyn Geirionydd Llyn Geirionydd Llyn Geirionydd lies in a valley in North Wales where the northern edge of the Gwydyr Forest meets the lower slopes of the Carneddau mountains. The lake is almost a mile long and covers an area of , but is never any deeper than according to Jehu’s survey ...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		45
Llyn Goddionduon Llyn Goddionduon Llyn Goddionduon is a remote lake in the Gwydir Forest in north Wales.It lies at a height of and covers an area of . It is totally surrounded by coniferous forest, although a track leads up to it, enabling a water supply in the event of fire, and anglers also use this path.It is unusual in that...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		10
Ffynnon Lloer Ffynnon Lloer Ffynnon Lloer is a lake in the Carneddau range of mountains in Snowdonia, North Wales. It lies below the peaks of Pen yr Ole Wen and Carnedd Dafydd at a height of and covers an area of some ....	River Ogwen River Ogwen The Afon Ogwen is a river in north-west Wales draining from some of the greatest peaks in Snowdonia before discharging to the sea on the eastern side of Bangor, Gwynedd.- Source :...		6
Ffynnon Llugwy Ffynnon Llugwy Ffynnon Llugwy is a lake in the Carneddau range of mountains in Snowdonia, North Wales.It lies at a height of about and covers an area of some...	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		40
Llynnau Mymbyr Llynnau Mymbyr Llynnau Mymbyr are two lakes located in Dyffryn Mymbyr, a valley running from the village of Capel Curig to the Pen-y-Gwryd hotel in Snowdonia, north-west Wales. The A4086 runs along their northern banks....	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		58
Llyn Ogwen Llyn Ogwen Llyn Ogwen is a lake in north-west Wales. It lies alongside the A5 road between two mountain ranges of Snowdonia, the Carneddau and the Glyderau...	River Ogwen River Ogwen The Afon Ogwen is a river in north-west Wales draining from some of the greatest peaks in Snowdonia before discharging to the sea on the eastern side of Bangor, Gwynedd.- Source :...		78
Llyn y Parc	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		22

Denbighshire

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Brickfields Pond	River Clwyd River Clwyd The River Clwyd is a river in North Wales which rises in the Clocaenog Forest northwest of Corwen.It flows due south until at Melin-y-Wig it veers northeastwards, tracking the A494 to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd...		8.9	Local Nature Reserve Local Nature Reserve Local nature reserve or LNR is a designation for nature reserves in the United Kingdom. The designation has its origin in the recommendations of the Wild Life Conservation Special Committee which established the framework for nature conservation in the United Kingdom and suggested a national suite...
Llyn Brân			31.4
Llyn Brenig Llyn Brenig Llyn Brenig is a reservoir located in North Wales, in the heart of the Denbigh Moors, on the border between the counties of Conwy and Denbighshire...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		920	Flow regulation
Llyn Cyfynwy			17.5
Llyn Gweryd			13.1
Llyn Mynyllod			6.2
Nant-y-Ffrith Reservoir			12.1
Pendinas Reservoir			16.3
Rhyl Marine Lake	River Clwyd River Clwyd The River Clwyd is a river in North Wales which rises in the Clocaenog Forest northwest of Corwen.It flows due south until at Melin-y-Wig it veers northeastwards, tracking the A494 to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd...		28.7
unnamed lake on Rûg Rug RUG or rug can mean:* carpet, a textile floor covering that is made from various materials.** specifically, one made by rug making* slang for toupee* rug , to keep domesticated animals warm and/or dry...  estate	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		8.4

Flintshire

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llyn Helyg	River Clwyd River Clwyd The River Clwyd is a river in North Wales which rises in the Clocaenog Forest northwest of Corwen.It flows due south until at Melin-y-Wig it veers northeastwards, tracking the A494 to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd...		37
Padeswood Pool			12.6	angling
Shotwick Lake	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....			amenity
unnamed reservoir, Cilcain Cilcain Cilcain is a small community, near Mold in Flintshire, north-east Wales. The village has an industrial history and includes the Millennium Woods, a post office, a public house, a parish church and a village hall....			5.4
unnamed reservoir, Oakenholt Oakenholt Oakenholt is a village in Flintshire, Wales. It is situated to the south east of the town of Flint, near the A548 road. At the 2001 Census, the population of the Flint Oakenholt Ward was 2,920.- External links :*...			5.7
Ysceifiog Lake			13.8

Gwynedd

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llyn yr Adar	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		10
Llyn Anafon	Afon Aber Afon Aber The Afon Aber is a small river in Gwynedd that enters Liverpool Bay on the coast of North Wales at Abergwyngregyn, . It rises in the Carneddau mountains on the northern watersheds of Drum, Foel Fras and Garnedd Uchaf and the eastern watersheds of Drosgl and Moel Wnion...		13	Water supply
Llyn Arenig Fach			34	Natural lake
Llyn Arenig Fawr Llyn Arenig Fawr Llyn Arenig Fawr is a lake and reservoir located near the summit of Arenig Fawr, a mountain in North Wales.The lake's primary purpose is to supply water to the nearby town of Bala and the numerous small villages in the surrounding area. From the lake it is an energetic uphill walk to the summit of...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		84	water supply for Bala town
Llynnau Barlwyd	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		10 + 5	Industrial water supply
Llyn y Bi	River Mawddach River Mawddach The River Mawddach is a river in North Wales which has its source in a wide area north of Dduallt in Snowdonia. The river is much branched and many of the significant tributaries are of a similar size to the main river...		6
Llyn Bodlyn	Afon Ysgethin		42	Water supply
Llyn Bowydd	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		22	Industrial water supply.
Llyn Caerwych	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		5
Llyn Cau	River Dysynni River Dysynni The River Dysynni is a river in mid Wales.- Source :The River Dysynni flows from the western end of Tal-y-llyn Lake and enters Cardigan Bay through the Broad Water lagoon to the north of Tywyn near Tonfanau.-External links:**...		33
Llyn Celyn Llyn Celyn Llyn Celyn is a large reservoir constructed between 1960 and 1965 in the valley of the River Tryweryn in Gwynedd, North Wales. It measures roughly 2½ miles long by a mile wide, and has a maximum depth of...	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		815	River Regulation
Llyn Conglog	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		18
Llyn Conglog Mawr	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		8
Craiglyn Dyfi also written as Creiglyn Dyfi	River Dyfi River Dyfi The River Dyfi is a river in Mid Wales. The Dyfi estuary forms the border between the counties of Gwynedd and Ceredigion.- Source :...		15	Natural corrie lake
Llyn Croesor	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		5
Llyn Cwm Corsiog			7	Industrial water supply (disused)
Llyn Cwellyn Llyn Cwellyn Llyn Cwellyn is a reservoir in North Wales which supplies drinking water to parts of Gwynedd and Anglesey. It lies on the Afon Gwyrfai in Nant y Betws between the Snowdon Massif and Mynydd Mawr in the northern part of Snowdonia National Park. It has an area of , and is over deep...	Afon Gwyrfai		215	Water supply
Llyn Cwm Bychan Llyn Cwm Bychan Llyn Cwm Buchan is a lake in north Wales, and is one of the sources of the River Artro which flows south westwards through Llanbedr and onwards to the sea....	Afon Artro		25
Llyn Cwm Dulyn	River Llyfni		34	Water supply
Llyn Cwmffynnon	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		20
Llyn Cwm-mynach	River Mawddach River Mawddach The River Mawddach is a river in North Wales which has its source in a wide area north of Dduallt in Snowdonia. The river is much branched and many of the significant tributaries are of a similar size to the main river...		14
Llyn Cwmorthin	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		22
Llynnau Cwm Silyn	River Llyfni		15 + 15
Llyn Cwm y Foel	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		8
Llyn Cwmystradllyn	River Dwyfor		98	Natural lake
Llyn Cynwch	River Mawddach River Mawddach The River Mawddach is a river in North Wales which has its source in a wide area north of Dduallt in Snowdonia. The river is much branched and many of the significant tributaries are of a similar size to the main river...		26	Amenity
Llyn Dinas Llyn Dinas Llyn Dinas is a lake near Beddgelert, Gwynedd in north Wales. It is formed by the River Glaslyn.Llyn Dinas lies on the valley floor a few miles north of Beddgelert at an altitude of about 55 metres above sea level. It has an area of and is fairly shallow, with the maximum depth only 10 metres...	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		60	Natural lake
Llynnau Diwaunedd	River Conwy River Conwy The River Conwy is a river in north Wales. From its source to its discharge in Conwy Bay it is a little over long. "Conwy" is sometimes Anglicized as "Conway."...		19 + 13	Natural lakes
Llyn Dulyn Llyn Dulyn Llyn Dulyn is a lake on the edge of the Carneddau range of mountains in Snowdonia, North Wales.The lake covers an area of only , yet is extremely deep - it reaches to a depth of 189'...	Afon Ysgethin		5	Natural lake
Llyn Du'r Arddu	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...		5	Natural lake
Llyn Dwythwch	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...		24
Llyn y Dywarchen	Afon Gwyrfai		40
Llyn Edno	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		10
Llyn Eiddew-mawr	Afon Artro		22
Llyn Ffynnon y Gwas	Afon Gwyrfai		10
Llyn y Gadair	Afon Gwyrfai		50
Llyn Gwynant Llyn Gwynant Llyn Gwynant is a lake in Snowdonia, Wales.Llyn Gwynant lies on the River Glaslyn, in the Nant Gwynant valley, and is about 2 km north east of Llyn Dinas; the village of Bethania lies between them....	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		85
Llyn Hesgyn	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		5
Llyn Hywel			13
Llyn Idwal Llyn Idwal Llyn Idwal is a small lake that lies within Cwm Idwal in the Glyderau mountains of Snowdonia.It is named after a son of Owain Gwynedd, one of the ancient Princes of Wales, legend stating that the unfortunate offspring was murdered by being drowned in the lake.A number of small streams flow into...	River Ogwen River Ogwen The Afon Ogwen is a river in north-west Wales draining from some of the greatest peaks in Snowdonia before discharging to the sea on the eastern side of Bangor, Gwynedd.- Source :...		28
Llyn Llagi	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		8
Llyn Llydaw Llyn Llydaw Llyn Llydaw is a lake in Snowdonia National Park on the flanks of Snowdon, Wales' highest mountain. This long thin lake has formed in a cwm about one-third of the way up the mountain....	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		110
Llyn Llywelyn	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		6
Llyn Mair Llyn Mair Llyn Mair is a artificial lake located at in North Wales. It lies in the area of Tan-y-Bwlch, a little above Plas Tan-y-Bwlch, and is in the catchment area of the River Dwyryd...	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		14
Marchlyn Bach reservoir	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...
Marchlyn Mawr Marchlyn Mawr Marchlyn Mawr reservoir is a high level lake in Snowdonia behind Elidir Fawr mountain. It is used as the high level water source for Dinorwig power station, a closed-loop pumped storage hydroelectric generating facility....	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...			Hydroelectricity
Llyn Mwyngil (Talyllyn Lake)	River Dysynni River Dysynni The River Dysynni is a river in mid Wales.- Source :The River Dysynni flows from the western end of Tal-y-llyn Lake and enters Cardigan Bay through the Broad Water lagoon to the north of Tywyn near Tonfanau.-External links:**...		220
Llyn Nantlle Uchaf Llyn Nantlle Uchaf Llyn Nantlle Uchaf is a lake in the Nantlle Valley, Gwynedd, Wales. The lake forms the foreground in Richard Wilson's painting "Snowdon from Llyn Nantlle" ....	Afon Llyfni Afon Llyfni The Afon Llyfni is a small river in North Wales which arises as Nant Drws y Coed between Mynydd Mawr and Mynydd Drws-y-Coed just to the west of Snowdon....		80
Llyn Newydd	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		12
Llyn Peris Llyn Peris Llyn Peris is a lake in Snowdonia, Wales, approximately 1.8 km long and situated close to the villages of Llanberis and Nant Peris. The lake was formed glacially and is an example of a moraine-dammed lake. Llyn Peris is named after Saint Peris, an early Christian saint of whom little is known...	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...		95
Llyn Padarn Llyn Padarn Llyn Padarn is a glacially formed lake in Snowdonia, Gwynedd, north Wales, and is an example of a moraine dammed lake. The lake is approximately long and at its deepest point is deep. At its south-eastern end it is linked to the neighbouring Llyn Peris...	River Seiont River Seiont Afon Seiont is a river in Gwynedd, Wales which runs into the Menai Strait.Its source is the outflow of Llyn Padarn near Llanberis, and it flows out in a generally northwest direction. Between the outflow and the village of Llanrug it is known as the Afon Rhythallt, changing its name just after the...		280	Hydroelectricity
Tanygrisiau Reservoir	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		95
Llyn Tecwyn Isaf			7
Llyn Tecwyn Uchaf	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		31
Llyn Tegid – (Bala Lake)	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		1,196
Llyn Teyrn	River Glaslyn River Glaslyn The Afon Glaslyn is a river in Gwynedd, north-west Wales. Whilst not of great significance in terms of its length , it is one of Gwynedd's primary rivers, and has greatly influenced the landscape in which it flows....		5
Llyn Trawsfynydd Llyn Trawsfynydd Llyn Trawsfynydd is a large man-made reservoir situated near the village of Trawsfynydd in Gwynedd, North Wales. With a total surface area of 4.8 km² the reservoir is slightly more extensive than Wales's largest natural lake, Llyn Tegid .Originally created in 1928 as the header reservoir for...	River Dwyryd River Dwyryd The Afon Dwyryd is a river in Gwynedd, North Wales, which flows principally westwards draining to the sea into Tremadog Bay south of Porthmadog....		1,180	Nuclear and Hydroelectricity
Llyn Tryweryn	River Dee River Dee, Wales The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....		20
Llyn Wylfa			6

Merthyr Tydfil

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Cantref Reservoir Cantref Reservoir Cantref Reservoir is the middle of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park, mostly in the Powys unitary authority area and within the historic county boundaries of Breconshire...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Cyfarthfa Castle Lake	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			amenity
Dol-y-gaer Reservoir * (Pentwyn Reservoir)	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Llwyn-on Reservoir Llwyn-On Reservoir Llwyn-on Reservoir is the largest and southernmost of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park. The eastern half is in the Merthyr Tydfil unitary authority area and the western half is in the Rhondda...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Penywern Middle Pond	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			angling
Penywern Top Pond	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			angling
Pitwellt Pond	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			former reservoir (dam breached)
Pontsticill Reservoir Pontsticill Reservoir Pontsticill Reservoir or Taf Fechan Reservoir is a large reservoir on the Taf Fechan lying partly in the county of Powys and partly within the county borough of Merthyr Tydfil in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply

Monmouthshire

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Llandegfedd reservoir Llandegfedd Reservoir Llandegfedd Reservoir is a large 174 hectare water supply reservoir and is eight miles north of Newport in south Wales. The reservoir is very close to Pontypool, Cwmbran and Usk.-History:...	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...		434	Water supply
Pen-ffordd-goch Pond/Keepers Pond	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...			amenity
Wentwood reservoir	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...		41	Water supply

Neath Port Talbot

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Cwmwernderi Reservoir				reservoir
Eglwys Nunydd Eglwys Nunydd The Eglwys Nunydd is a large reservoir in Margam, South Wales originally constructed to provide water for the large steelworks at Margam and specifically for cooling water for the cold rolling mills at the eastern end of the works...	River Afan River Afan The River Afan is a river in southwest Wales whose river valley formed the territory of the medieval Lords of Afan. The town of Aberavon grew up on the banks of the river, and was later subsumed by the larger centre of population known as Port Talbot...		260	Industrial water supply + fishing
Furzemill Pond	River Afan River Afan The River Afan is a river in southwest Wales whose river valley formed the territory of the medieval Lords of Afan. The town of Aberavon grew up on the banks of the river, and was later subsumed by the larger centre of population known as Port Talbot...		5	former millpond?
Rheola Pond	River Neath River Neath River Neath is a river in south Wales running south west from its source in the Brecon Beacons National Park to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay.Several minor rivers rise on the southern slopes of Fforest Fawr...
larger un-named lake at Aberclwyd	River Neath River Neath River Neath is a river in south Wales running south west from its source in the Brecon Beacons National Park to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay.Several minor rivers rise on the southern slopes of Fforest Fawr...			amenity
smaller un-named lake at Aberclwyd	River Neath River Neath River Neath is a river in south Wales running south west from its source in the Brecon Beacons National Park to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay.Several minor rivers rise on the southern slopes of Fforest Fawr...			amenity

Pembrokeshire

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Bosherston ponds	Coastal stream			Natural lakes
Llys-y-Frân	Western Cleddau		212	Water supply
Rosebush Reservoir	Western Cleddau		30	Water supply

Powys

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Beacons Reservoir Beacons Reservoir Beacons Reservoir is the northernmost of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. As its name suggests, it is located in the Brecon Beacons National Park in the Powys unitary authority area and within the historic county boundaries of...	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...		52	Water supply
Caban-coch Reservoir	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...		500 (including Garreg-ddu Reservoir)	Water supply
Cantref Reservoir Cantref Reservoir Cantref Reservoir is the middle of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park, mostly in the Powys unitary authority area and within the historic county boundaries of Breconshire...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...		42	Water supply
Claerwen Reservoir	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...		664	Water supply
Llyn Clywedog	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...			River regulation
Craig-goch Reservoir	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...		217	Water supply
Cray Reservoir Cray reservoir Cray Reservoir is a storage reservoir located in the Brecon Beacons National Park for the water supply to the city of Swansea in South Wales and was built between 1898 and 1906 by Swansea Corporation....	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...		100	Water supply
Dol-y-gaer Reservoir * (Pen-twyn Reservoir)	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Garreg-ddu Reservoir	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...		500 (including Caban-coch Reservoir)	Water supply
Llyn Gludy	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...
Llangorse Lake Llangorse Lake Llangorse Lake is the largest natural lake in south Wales, and is situated in the Brecon Beacons National Park, near to the town of Brecon and the village of Llangors....	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...		327	Natural lake
Llwyn-on Reservoir Llwyn-On Reservoir Llwyn-on Reservoir is the largest and southernmost of the three reservoirs in the Taff Fawr valley in South Wales. It is owned by Welsh Water. It is located in the Brecon Beacons National Park. The eastern half is in the Merthyr Tydfil unitary authority area and the western half is in the Rhondda...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...		150	Water supply
Llyn y Fan Fawr Llyn y Fan Fawr Llyn y Fan Fawr is a natural lake in the county of Powys, Wales. It lies at the foot of Fan Brycheiniog, the highest peak of the Black Mountain range within the Brecon Beacons National Park....	River Tawe River Tawe The River Tawe is a river in South Wales. It flows in a principally south-westerly direction for some from its source below Moel Feity in the Old Red Sandstone hills of the western Brecon Beacons to the Bristol Channel at Swansea. Its main tributaries are the right bank Upper and Lower Clydach...
Lower Neuadd Reservoir	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Upper Neuadd Reservoir	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Penygarreg Reservoir	River Severn River Severn The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...		124	Water supply
Pontsticill Reservoir Pontsticill Reservoir Pontsticill Reservoir or Taf Fechan Reservoir is a large reservoir on the Taf Fechan lying partly in the county of Powys and partly within the county borough of Merthyr Tydfil in south Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark...  *	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...			Water supply
Talybont Reservoir Talybont Reservoir The Talybont Reservoir is the largest stillwater reservoir in the central Brecon Beacons at .-References:*- External links :*...	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...			Water supply
Ty Mawr Pool	River Usk River Usk The River Usk rises on the northern slopes of the Black Mountain of mid-Wales, in the easternmost part of the Brecon Beacons National Park. Initially it flows north into Usk Reservoir, then east by Sennybridge to Brecon before turning southeast to flow by Talybont-on-Usk, Crickhowell and...			natural lake
Lake Vyrnwy Lake Vyrnwy Lake Vyrnwy Nature Reserve and Estate is an area of land in Montgomeryshire, Powys, Wales, surrounding the Victorian reservoir of Lake Vyrnwy. Its stone-built dam, built in the 1880s, was the first of its kind in the world. The Nature Reserve and the area around it are jointly managed by the Royal...	River Vyrnwy River Vyrnwy The River Vyrnwy is a river which flows through northern Powys, Wales, and Shropshire, England.The river used to be sourced from the many rivers and streams running off the mountains surrounding the Vyrnwy valley. However, since the Lake Vyrnwy dam was built in the 1880s, the river has flowed...			Water supply
Ystradfellte Reservoir Ystradfellte Reservoir Ystradfellte Reservoir is a water storage reservoir on the Afon Dringarth in the upland area of Fforest Fawr within the Brecon Beacons National Park in south Wales. It lies just north of the village of Ystradfellte in the county of Powys at OS Grid ref SN 946178.The embankment is long by high...	River Neath River Neath River Neath is a river in south Wales running south west from its source in the Brecon Beacons National Park to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay.Several minor rivers rise on the southern slopes of Fforest Fawr...			Water supply

Rhondda Cynon Taff

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Dare Valley Country Park lower lake	Afon Cynon			amenity
Lluest-wen Reservoir	Afon Rhondda Fach
Llyn Fawr Llyn Fawr Llyn Fawr is a lake in the Cynon Valley , South Wales, best known as the site of an important hoard of weapons and tools from the late Bronze Age and early Iron Age...	River Taff River Taff The River Taff is a large river in Wales. It rises as two rivers in the Brecon Beacons — the Taf Fechan and the Taf Fawr — before joining to form the Taff north of Merthyr Tydfil...		24
Nant-hir Reservoir	Afon Cynon
Nant-moel Reservoir	Afon Cynon
Penderyn Reservoir	River Neath River Neath River Neath is a river in south Wales running south west from its source in the Brecon Beacons National Park to its mouth at Baglan Bay below Briton Ferry on the east side of Swansea Bay.Several minor rivers rise on the southern slopes of Fforest Fawr...
?Perthgelyn Reservoir	Afon Cynon			reservoir

Swansea

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Lake Fendrod	River Tawe River Tawe The River Tawe is a river in South Wales. It flows in a principally south-westerly direction for some from its source below Moel Feity in the Old Red Sandstone hills of the western Brecon Beacons to the Bristol Channel at Swansea. Its main tributaries are the right bank Upper and Lower Clydach...		13	Amenity
Lower Lliw Reservoir	River Lliw			Water Supply
Oxwich Marsh Lake	coastal stream		>15	Natural lake
Upper Lliw Reservoir	River Lliw			Water Supply
Tawe Barrage River Tawe The River Tawe is a river in South Wales. It flows in a principally south-westerly direction for some from its source below Moel Feity in the Old Red Sandstone hills of the western Brecon Beacons to the Bristol Channel at Swansea. Its main tributaries are the right bank Upper and Lower Clydach...	River Tawe River Tawe The River Tawe is a river in South Wales. It flows in a principally south-westerly direction for some from its source below Moel Feity in the Old Red Sandstone hills of the western Brecon Beacons to the Bristol Channel at Swansea. Its main tributaries are the right bank Upper and Lower Clydach...			Amenity
Specimen Lake	River Loughor River Loughor The River Loughor in Carmarthenshire, Wales has its source at an underground lake at the Black Mountain. It flows past settlements like Ammanford and Hendy in Carmarthenshire and Pontarddulais in Swansea. The river divides Carmarthenshire from Swansea for much of its course and it separates Hendy...		10	amenity/angling

Torfaen

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Blaen Bran Reservoir (lower)	Afon Lwyd
Coity Pond	Afon Lwyd			former reservoir

Vale of Glamorgan

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Cosmeston Lake Cosmeston Park Cosmeston Lakes Country Park is a public country park in Britain. It is situated between Lower Penarth and Sully, Vale of Glamorgan, 7.3 miles from Cardiff. The park is open all year and access is free, but its visitor centre is usually closed in winter.-General:At its centre the park features a...	River Cadoxton			Amenity
Hensol Lake	River Ely River Ely The River Ely is a river in South Wales flowing generally south east, from Tonyrefail to the capital city of Cardiff.-Course of the river:...			Amenity and reservoir
Hensol Mill Pond	River Ely River Ely The River Ely is a river in South Wales flowing generally south east, from Tonyrefail to the capital city of Cardiff.-Course of the river:...		6	former mill pond

Wrexham

Lake name	Catchment	Grid ref.	Area (acres)	Status/Use
Cae Llwyd Reservoir			10.6
Fenn's Bank Mere			8.4
Gresford Flash			8.2	amenity
Hanmer Mere Hanmer Mere Hanmer Mere is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales....			45.2	natural lake
Monk's Pool			5.2
Newhall Reservoir			11.1
Pant-yr-ochain Lake			14.1
Penycae Top Reservoir			6.2
Ty Mawr Reservoir			21.3
Wynnstay Park Lake Wynnstay Wynnstay was a famous estate in Wales, the family seat of the Wynns. It is located at Ruabon, near Wrexham.During the 17th century, Sir John Wynn, 5th Baronet inherited the Watstay Estate through his marriage to Jane Evans , and renamed it the Wynnstay Estate...			8.9