Afon Gwydderig

The Afon Gwydderig is a

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

of the

Afon Brân The Afon Brân is a tributary of the River Towy (or Welsh Afon Tywi) in mid Wales. Its headwaters rise in Irfon Forest in the northeastern corner of Carmarthenshire as the Cynnant Fawr and Afon Lwynor and the river assumes the name of Afon Brâ ...

. It rises as the Nant Gwydderig on the southern slopes of Mynydd Bwlch-y-groes, about North of the small village of Llywel,

Powys Powys (; ) is a county and preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh successor state, petty kingdom and principality that emerged during the Middle Ages following the end of Roman rule in Britain. Geog ...

. The A40 runs next to the river from Llywel as far as

Llandovery Llandovery (; cy, Llanymddyfri ) is a market town and community in Carmarthenshire, Wales. It lies on the River Tywi and at the junction of the A40 and A483 roads, about north-east of Carmarthen, north of Swansea and west of Brecon. Hi ...

Carmarthenshire Carmarthenshire ( cy, Sir Gaerfyrddin; or informally ') is a county in the south-west of Wales. The three largest towns are Llanelli, Carmarthen and Ammanford. Carmarthen is the county town and administrative centre. The county is known as ...

. The Gwydderig crosses the boundary between Powys and Carmarthenshire at the village of Halfway. It joins the Brân in Llandovery, Carmarthenshire, about upstream of the confluence of the Brân with the

River Towy The River Towy ( cy, Afon Tywi, ) is one of the longest rivers flowing entirely within Wales. Its total length is . It is noted for its sea trout and salmon fishing. Route The Towy rises within of the source of the River Teifi on the lower s ...

. The Gwydderig therefore forms part of the Towy's

catchment basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the ...

and drains into the Bristol Channel at the Towy estuary. Rivers of the Brecon Beacons National Park Rivers of Carmarthenshire Rivers of Powys {{Wales-river-stub