Saint Thomas is one of the Virgin Islands in the Caribbean Sea, and a constituent district of the United States Virgin Islands, an unincorporated territory of the United States. Along with surrounding minor islands, it is one of three county-equivalents in the USVI. Together with Saint John, it forms one of the districts of the USVI. The territorial capital and port of Charlotte Amalie is located on the island. Of the three islands, St. Thomas is the second-largest, with St. Croix being the largest, and St. John, the smallest.