Bonin Islands (bō´nīn), Jap. Ogasawara-gunto, volcanic island group, c.40 sq mi (100 sq km), in the W Pacific Ocean, c.500 mi (800 km) S of Tokyo; part of Tokyo prefecture, Japan. The largest and principal island is Chichi (formerly Peel Island), c.10 sq mi (30 sq km), the site of Omura, the capital of the group, and Futami-ko (Port Lloyd), the chief harbor. The principal products are timber and fruit, such as bananas and pineapples. The majority of the inhabitants are Japanese; there are some Koreans and Taiwanese. The islands were claimed by Japan from the British in 1875 and placed under the Tokyo prefecture in 1880. In World War II the islands formed a major Japanese military stronghold until they were occupied by the U.S. navy in 1945. The islands were administered by the U.S. military until 1968, when they were returned to Japan.