one of the Mariana Islands and part of the Northern Mariana Islands, a commonwealth of the United States, in the western Pacific Ocean. It lies about 100 miles (160 km) north of Guam. Of volcanic formation, it rises to an elevation of 614 feet (187 metres). Tinian was administered by Japan before World War II and became a major sugarcane-growing and sugar-processing centre. After its capture by U.S.-led Allied forces in 1944, the island was converted into a major U.S. military air base, equipped with what were then the world's longest runways. In August 1945 two U.S. bombers based at Tinian dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. A large part of the island is still leased by the U.S. military. The economy is little developed, with some cultivation of vegetables for export to Guam and a small beef-cattle industry. The main town, San Jose, is on the southwest coast. Area 39 square miles (101 square km). Pop. (2000) including the adjacent island of Aguijan, 3,540.