Carrigafoyle Castle - built by Conor Liath O'Connor-Kerry in the 1490s and considered one of the strongest of Irish fortresses - was a large tower house, of the type particularly common across the north of the province of Munster. It stood on a rock in a small bay off the Shannon estuary, and its name is an anglicisation of the Irish, Carraig an Phoill ("rock of the hole").