(sän hwän dĕl nôr'tā) , small town, SE Nicaragua, on the Caribbean Sea. Small quantities of bananas and hardwoods are exported. Also called Greytown, it was occupied (1848) by the British to secure control of the Mosquito Coast and to check the U.S. efforts to build an interoceanic canal. The port became the thriving eastern terminus of a transisthmian transport company operated by Cornelius Vanderbilt in the gold rush to California. In 1854 it was bombarded by the U.S. warship Cyane in retaliation for insults to the U.S. minister and damage to U.S. property in Nicaragua. San Juan was important in the filibustering activities of William Walker.