Barmouth Bridge (Welsh: Pont Abermaw), or Barmouth Viaduct is a Grade II* listed single-track wooden railway viaduct across the estuary of the Afon Mawddach near Barmouth, Wales.
It is 820 metres (900 yd) long and carries the Cambrian Line.
It is the longest timber viaduct in Wales and one of the oldest in regular use in Britain.