Bonacca (formerly called Guanaja), an island in Honduras bay, Caribbean sea, 30 m. N. of Cape Castilla; lat. 16° 28' K, Ion. 85° 55' W. It is the second in size of the group called the Bay Islands, is about 9 m. long and from 1 to 3 m. broad, and rises to a height of 1,200 ft. The island was discovered by Columbus in his fourth and last voyage, July 30, 1502. The aborigines had made considerable advances in civilization, and carried on an active trade by means of large boats with the mainland of Honduras and Yucatan, and, it is said, even with Jamaica. The Spaniards and afterward the buccaneers harassed them so much that they abandoned the island in 1642, and took refuge on the mainland. The buccaneers fortified the island and held it till 1650, when they were expelled by the Spaniards. In 1742 the English seized Bonacca and the neighboring island of Ruatan, which they fortified and held till it was captured by the Spaniards in 1782. When Central America became independent in 1821 Bonacca and the other islands of the group came under the jurisdiction of Honduras. In 1850 a British naval commander declared them under the sovereignty of Great Britain, and in 1852 the group was constituted by royal proclamation the British " Colony of the Bay Islands." This act, being in contravention of the convention between England and the United States known as the "Clayton and Bulwer treaty," led to an animated controversy between the British and American governments, which was at length settled by restoring the islands to Honduras in 1859.