The Afon Mawddach is a celebrated Welsh river flowing through the dramatic landscapes of southern Snowdonia National Park, ultimately emptying into the Mawddach Estuary near Barmouth. The catchment is broadly divided into two major subcatchments: the Mawddach subcatchment to the north, which drains upland moorland that has been extensively afforested, and the Wnion subcatchment to the south and south-east, which joins the Mawddach Estuary approximately 1km downstream of the upper tidal influence on the main river. The river is renowned as one of Wales's top salmon and sea trout fisheries, with the Dolgellau Angling Association (DAA) controlling large sections of both the Mawddach and its principal tributary, the Wnion, offering over 13 miles of prime game fishing water.