Tarren y Gesail is a mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

 in Snowdonia

Snowdonia

Snowdonia is a region in north Wales and a national park of in area. It was the first to be designated of the three National Parks in Wales, in 1951.-Name and extent:...

, North Wales

North Wales

North Wales is the northernmost unofficial region of Wales. It is bordered to the south by the counties of Ceredigion and Powys in Mid Wales and to the east by the counties of Shropshire in the West Midlands and Cheshire in North West England...

. It is one of the Marilyn

Marilyn

Marilyn is a feminine given name. Notable people with the name include:*Marilyn , British entertainer*Marilyn Agliotti , Dutch-South African field hockey player...

s of the Cadair Idris

Cadair Idris

Cadair Idris or Cader Idris is a mountain in Gwynedd, Wales that lies at the southern end of the Snowdonia National Park. The peak, which is one of the most popular in Wales for walkers and hikers,  is composed largely of Ordovician igneous rocks, with classic glacial erosion features such as...

 group.

Lying to the south of Cadair Idris, it and its neighbour Tarrenhendre

Tarrenhendre

Tarrenhendre is a mountain in Snowdonia, North Wales. It is one of the Marilyns in the Cadair Idris group.Lying to the south of Cadair Idris, it and its neighbour Tarren y Gesail form the bulk of the Tarren subgroup...

 form the bulk of the Tarren subgroup. The Tarrens rise from the south shore of the Tal-y-llyn Lake

Tal-y-llyn Lake

Tal-y-llyn Lake, also known as Talyllyn Lake or Llyn Mwyngil, is a large glacial ribbon lake formed by a post-glacial massive landslip damming up the lake within the glaciated valley...

 and end at the Dyfi estuary

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 :...

.

The summit is a grassy ridge, which has a cairn

Cairn

Cairn is a term used mainly in the English-speaking world for a man-made pile of stones. It comes from the or . Cairns are found all over the world in uplands, on moorland, on mountaintops, near waterways and on sea cliffs, and also in barren desert and tundra areas...

 and trig point

Triangulation station

A triangulation station, also known as a triangulation pillar, trigonometrical station, trigonometrical point, trig station, trig beacon or trig point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity...

. The views are extensive to the south and east, with Plynlimon

Plynlimon

Plynlimon is the highest point of the Cambrian Mountains in Wales, and the highest point in Mid Wales. It is a massif that dominates the countryside of northern Ceredigion....

 and Cardigan Bay

Cardigan Bay

Cardigan Bay is a large inlet of the Irish Sea, indenting the west coast of Wales between Bardsey Island, Gwynedd in the north, and Strumble Head, Pembrokeshire at its southern end. It is the largest bay in Wales....

 ahead, while the north views are dominated by Cadair Idris and Maesglase

Maesglase

Maesglase is a mountain in Snowdonia, North Wales, situated approximately four miles to the south-west of Aran Fawddwy. It is the highest of the "Dyfi Hills"....

to the west.

The Tarrerns can be thought of as forgotten mountains of Snowdonia, overshadowed by the popularity of Cadair Idris, occupying the sleepy south-eastern frontier of the national park.