Dursey Island lies at the southwestern tip of the Beara Peninsula in the west of County Cork in Ireland. Dursey Island is 6.5 kilometres long and 1.5 kilometres wide. The island is separated from the mainland by a narrow stretch of water, Dursey Sound, which has a very strong tidal race, with the submerged Flag Rock close to the centre of the channel.

Beara or the Beara Peninsula is a peninsula on the south-west coast of Ireland, bounded between the Kenmare "river" to the north side and Bantry Bay to the south. It contains two mountain ranges running down its centre: the Caha Mountains and the Slieve Miskish Mountains. The northern part of the peninsula from Kenmare to near Ardgroom is in County Kerry, while the rest forms the barony of Bear in County Cork.