island off the south coast of Brittany, western France, 8 miles (13 km) southwest of Presqu'Île de Quiberon and administratively part of Morbihan département, Bretagne région. As an outpost of the mainland ports of Saint-Nazaire and Lorient, a citadel on the island was strategically important to France from 1572 to the 19th century. Occupied by the British in 1761–63, it was returned to France by the same treaty that yielded Nova Scotia to Great Britain. It has several fishing settlements, the largest being Le Palais. Its economic basis is agricultural, especially grains, supplemented by fishing and tourism. Area 32 square miles (83 square km).