The Afon Mawddach is a river in Gwynedd, Wales, which has its source in a wide area SH820300 north of Dduallt in Snowdonia. It is 28 miles (45 km) in length, and is much branched; 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.
The Mawddach looking west to Barmouth Bay
Waterfall on the Mawddach, 1816
The Mawddach in Coed-y-Brenin
A view across the Mawddach Estuary
Barmouth Bridge, or Barmouth Viaduct is a Grade II* listed single-track wooden railway viaduct across the estuary of the River Mawddach near Barmouth, Wales. It is 900 yards (820 m) long and carries the Cambrian Line. It is the longest timber viaduct in Wales and one of the oldest in regular use in Britain.
View of the bridge from Barmouth
The north end of the crossing has a swing bridge section to allow tall ships to pass, though it has not seen regular use since testing in the 1980s.
Illustration of the estuary and bridge, c. 1869
A steam-hauled train traversing Barmouth Bridge, c. 1921