Navassa Island is located in the Caribbean Sea, 99.4 mi (160 km) south of the U.S. naval base at Guantnamo, Cuba, between Cuba, Haiti, and Jamaica. The island has a total area of 2.01 sq mi (5.2 sq km). It was claimed for the U.S. in 1857 under the Guano Act. The Navassa Phosphate Company mined the island until 1900, enlisting hundreds of freed American slaves to dig out several tons of guano. Working conditions were so brutal that the laborers revolted in 1889, killing their supervisors. The island is also claimed by Haiti.