Espiritu Santo, also Santo, largest island of Vanuatu, formerly the New Hebrides, in the western Pacific Ocean. The first European to reach the island was the Portuguese explorer Pedro de Queirós, who came upon it in 1606. Thinking he had reached Australia, he named it Australia des Espiritu Santo. In early 1942, after the start of World War II in the Pacific, American forces established military and naval bases here. In May 1980, shortly before the New Hebrides was due to gain independence, Espiritu Santo was seized by separatist rebels; the rebellion was suppressed in August 1981. Area, 4,860 sq km (1,870 sq mi); population (1989, Santo-Malo region) 25,350.