Achill Island (; ) in County Mayo is the largest of the Irish isles, and is situated off the west coast of Ireland. It has a population of 2,594. Its area is . Achill is attached to the mainland by Michael Davitt Bridge, between the villages of Gob an Choire (Achill Sound) and Poll Raithní (Polranny). A bridge was first completed here in 1887. Other centres of population include the villages of Keel, Dooagh, Dumha Éige (Dooega), Dún Ibhir (Dooniver), and Dugort. The parish's main Gaelic football pitch and secondary school are on the mainland at Poll Raithní. Early human settlements are believed to have been established on Achill around 3000 BC.