The only fjord in Ireland is reputed be a glacial formation. Its centre has a depth of 45 meters and it is 16 kilometers in length. It is part of the border between Galway and Mayo.

To the north one can see the mighty mountain of Mweelrea which has a height of 817 meters. At the side, to the south, is the hamlet named Rossroe. A now disused hostel was converted into a house and it was here that the philosopher Ludwig Wittgenstein wrote after the Second World War ended. In 1993 President Mary Robinson unveiled a plaque there in his remembrance. The Green Road stretches along the side of the fjord for nine kilometers. In the nineteenth century it played a part in the famine relief programme.

Fishing is lucrative here. There is a salmon farm at Rossroe. Further to the east one can see mussel rafts.