Achill Island

island, Ireland

Written and fact-checked by The Editors of Encyclopaedia Britannica

Last Updated: Oct 22, 2024 • Article History

Achill Island, mountainous island off the west coast of Ireland. It is part of County Mayo, joined to the mainland by a bridge across Achill Sound. The island is Ireland’s largest, with an area of 56 square miles (145 square km), and its highest points are the quartzite peaks of Slieve Croaghaun (2,182 feet [665 metres]) and Slieve More (2,201 feet [671 metres]). The landscape is dominated by wild moorlands and spectacular coastal scenery. Farming and fishing are vital to the economy. With its many beaches and fine cliffs, the island attracts a significant number of tourists. An annual seafood festival is held during the summer. In the south, at Kildavnet, there are ruins of a 12th-century church and a 15th-century castle.

This article was most recently revised and updated by Michael Ray.