Not to be confused with the Afon Marlais

Afon Marlais, Pembrokeshire

The Afon Marlais is a right-bank tributary of the River Tâf in Pembrokeshire, West Wales. It flows through the Vale of Lampeter to join the Tâf just west of Whitland. The name derives from the Welsh 'marw glais' and signifies a 'stagnant stream'....

 which is a tributary of the River Tâf

River Tâf

The River Tâf is a river that rises in the Preseli Hills of North Pembrokeshire, West Wales, near the village of Crymych and is around 50 km long....

 nor the Afon Marlas

Afon Marlas

The Afon Marlas is a minor right-bank tributary of the River Loughor in eastern Carmarthenshire, West Wales. It rises north of the village of Llandybie and flows southwards through that village and joins the Loughor on the northwestern edge of Ammanford near Aberlash Mill....

, a tributary of the 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...

.

The Afon Marlais is a right-bank tributary of the River Towy in Carmarthenshire

Carmarthenshire

Carmarthenshire is a unitary authority in the south west of Wales and one of thirteen historic counties. It is the 3rd largest in Wales. Its three largest towns are Llanelli, Carmarthen and Ammanford...

, West Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

. It rises on the slopes of Mynydd Llanfihangel-rhos-y-corn and Mynydd Tre-beddau and flows south-eastwards through Brechfa Forest

Brechfa Forest

The Brechfa Forest is an area of forest in Carmarthenshire, south Wales.Much of the planting took place during the 1930s, with work carried out by young unemployed men from a Ministry of Labour work camp...

 before reaching the village of Brechfa

Brechfa

Brechfa is a village in Carmarthenshire, Wales that has existed since the 6th century.- Location and amenities :Brechfa is set in countryside managed by the Forestry Commission or Forest Enterprise at the top of the Cothi Valley. The village is the site of Brechfa Mountain Biking...

. After a further kilometre it joins the Towy immediately downstream of Pont Ynys-Brechfa.