Ireland, Republic of (officially Eire), a country of Europe occupying most of the island of Ireland. It is bounded on the northeast by Northern Ireland, on the east by the Irish Sea, on the southeast by St. George's Channel, and on the southwest, west, and north by the Atlantic. The area is 27,135 square miles (70,280 km 2). Maximum distances are 235 miles (380 km) north-south and 175 miles (280 km) east-west.