A settlement with a coastguard station on the southeast coast of the island of Arran, Kildonan lies 3 miles (5 km) south of Whiting Bay. It is said to be associated with St Donan who trained at Whithorn. The ruined Kildonan Castle dates from the 14th century and nearby are Drimla Lodge (1896) and the Lagg Hotel. Kildonan looks out over the Sound of Pladda to the island of Pladda on which stands a lighthouse built in 1790 by Thomas Smith.