Clare Island, island, lying at the entrance to Clew Bay, County Mayo, Ireland, and covering 6 square miles (16 square km). On the northwest, quartzite hills rise to 1,507 feet (459 metres) with a scarped cliff (Knockmore), and on the east and south there is a small amount of farm land. The exposure of the island to sea winds tends to stunt all tree growth. Gráinne Uaile, or ní Mháille (Grace O’Malley), the 16th-century queen of the island, is buried in the Carmelite abbey (1224).