"Mayo, a county of Ireland, province of Connaught, 62 m. long and 52 broad, bounded E by Roscommon, S by Galway, W and N by the Atlantic, and NE by Sligo, 54 m. long, and 48 broad, and containing 796,000 acres, divided into 68 parishes. It sends 2 members to parliament. The W coast is mountainous, and thinly inhabited; but the interior produces excellent pasturage, and is watered by several lakes and rivers. Pop. 297,538. Chief town, Castlebar."
[From The New London Gazetteer (1826)]