Achill, par., including Achill and Achillbeg islands, W. co. Mayo, 51,521 ac., pop. 6732. Achill Island, the largest island off the Irish coast, is crescent-shaped and measures 15 miles between its extreme points, with an average breadth of 4 miles. Achill Sound is a narrow strait separating the island from Curraun peninsula (which is included in the par.), and gives its name to the P.O. of the island. Achill Head is a bold prom. on the SW., alt. 2192 ft. Achillbeg Island, 1½ miles long, lies at the S. entrance of A. Sound. The inhabitants of the islands and dist. are chiefly employed in fishing.

(John Bartholomew, Gazetteer of the British Isles (1887))