ʿEua, volcanic and limestone island in the Tongatapu Group of Tonga, southwestern Pacific Ocean. The second largest of the group, ʿEua is hilly and rises to an elevation of 1,078 feet (329 metres). Sighted in 1643 by the Dutch navigator Abel Janszoon Tasman, the island was originally named Middleburg. ʿEua has a number of government-run primary schools and several church-administered middle and secondary schools. The leading economic sectors are agriculture (vanilla, kava, and root crops) and tourism; forestry also contributes income. Area 33.7 square miles (87.4 square km). Pop. (2006 prelim.) 5,165.