River Mawddach

The Afon Mawddach is a river in Gwynedd, Wales, which has its source in a wide area north of Dduallt in Snowdonia. The river is much branched and many of the significant tributaries are of a similar size to the main river. The catchment area is bounded to the east by the Aran Fawddwy massif and to the west and north by the Harlech dome which forms a watershed just south of Llyn Trawsfynydd.