Devils Island, Fr. Île du Diable, the smallest and southernmost of the Îles du Salut, in the Caribbean Sea off French Guiana. A penal colony founded in 1852, it was used largely for political prisoners, the most celebrated of whom was Alfred Dreyfus. Although conditions were probably not as sordid as in other prison camps in French Guiana, the island's name became synonymous with the horrors of the system. The penal colonies were phased out between 1938 and 1951.