Afon Twrch

For other rivers, see Afon Iwrch and Afon Twrch, Carmarthenshire.

Afon Twrch
Ribbon of river in shadow reflecting the sky, bending back and forth through a valley between moorland hills of grey scree and brown and green vegetation
Afon Twrch looking south downstream from the side of Pen yr Helyg
Map
Etymologyafon / 'river' and twrch / 'boar'.
Location
CountryWales
Physical characteristics
Source 
 • locationSouthern slopes of Bannau Sir Gaer (Carmarthen Fans) and Fan Brycheiniog
 • coordinates51°52′49″N 3°42′39″W / 51.880359°N 3.710933°W / 51.880359; -3.710933
 • elevation770 metres (2,530 ft)
Mouth 
 • location
River Tawe at Ystalyfera
 • coordinates
51°45′40″N 3°46′55″W / 51.761194°N 3.782022°W / 51.761194; -3.782022
 • elevation
70 metres (230 ft)
Length8.7 miles (14 km)
Basin features
River systemRiver Tawe
Tributaries 
 • leftNant Gwys
 • rightNant Lluestau, Nant Manyn, Nant Y Ddraenen, Twrch Fechan, Nant Y Llyn, Nant Llynfell

The Afon Twrch is a river which rises in the Black Mountain in south Wales. It forms the boundary between Powys and Carmarthenshire and, downstream of Ystradowen, between Powys and Neath Port Talbot.