Achill Island is located off the west coast of Ireland in the historical barony of Burrishoole, County Mayo. It is the largest of the Irish isles, covering an area of approximately 148 km2 (57 sq mi). The island has been connected to the mainland by a bridge since 1887, specifically via the Michael Davitt Bridge which connects the villages of Achill Sound and Polranny.
The island had a population of 2,345 as of the 2022 census. Other notable centers of population on the island include the villages of Keel, Dooagh, Dooega, Dooniver, and Dugort. The landscape is characterized by several peat bogs.