Bonin Islands (Japanese Ogasawara-Gunto), also known as Bonins, group of volcanic islands in the western Pacific Ocean, Japan, near the tropic of Cancer. The small islands were formerly part of Tokyo Prefecture. The principal islands are Chichi, Haha, Ototo, Mukai, and Yome. Sugarcane, pineapples, and bananas are cultivated, and there are valuable stands of timber, notably palm cedar, ironwood, boxwood, rosewood, and sandal trees. The islands were formally annexed by Japan in 1876. After the surrender of Japan in August 1945, the Bonins remained under U.S. control until June 1968, when they were returned to Japan. Area, 100 sq km (40 sq mi); population (1985) 2,303.