The Royal Society for the Protection of Birds reserve at Ynys-hir has one of the most beautiful settings of any in southern Britain. It lies on the estuary of the River Dyfi (or Dovey), on the borders of North and South Wales, ringed by mountains and wooded slopes. The reserve runs from the saltmarsh and boggy ground of the floodplain, high up onto the adjacent hills, comprising a total of over 420ha.