ACHILL (“Eagle”), the largest island off Ireland, separated from the Curraun peninsula of the west coast by the narrow Achill Sound. Pop. (1901) 4929. It is included in the county Mayo, in the western parliamentary division. Its shape is triangular, and its extent is 15 m. from E. to W. and 12 from N. to S. The area is 57 sq. m. The island is mountainous, the highest points being Slieve Croaghaun (2192 ft.) in the west, and Slievemore (2204 ft.) in the north; the extreme western point is the bold and rugged promontory of Achill Head, and the north-western and south-western coasts consist of ranges of magnificent cliffs, reaching a height of 800 ft. in the cliffs of Minaun, near the village of Keel on the south. The seaward slope of Croaghaun is abrupt and in parts precipitous, and its jagged flanks, together with the serrated ridge of the Head and the view over the broken coast-line and islands of the counties Mayo and Galway, attract many visitors to the island during summer. Desolate bogs, incapable of cultivation, alternate with the mountains; and the inhabitants earn a scanty subsistence by fishing and tillage, or by seeking employment in England and Scotland during the harvesting. The Congested Districts Board, however, have made efforts to improve the condition of the people, and a branch of the Midland Great Western railway to Achill Sound, together with a swivel bridge across the sound, improved communications and make for prosperity. Dugort, the principal village, contains several hotels. Here is a Protestant colony, known as “the Settlement” and founded in 1834. There are antiquarian remains (cromlechs, stone circles and the like) at Slievemore and elsewhere.