The River Gwydderig
of the River Bran
(Welsh: Afon Bran). It rises as the Nant
Gwydderig on the southern slopes of Mynydd Bwlch-y-groes, about 3 miles
(4.8 km) North of the small village of Llywel, Powys.
A40 runs next to the river from Llywel as
far as Llandovery, Carmarthenshire.
The Gwydderig crosses the boundary between Powys and
Carmarthenshire at the village of Halfway
the Bran in Llandovery, Carmarthenshire, about 1.5 miles upstream
of the confluence of the Bran with the River Towy. The River Gwydderig therefore forms part of
the Towy's catchment basin and
drains into the Bristol
Channel at the Towy estuary.