Saint John is one of the Virgin Islands in the Caribbean Sea and a constituent district of the United States Virgin Islands (USVI), an unincorporated territory of the United States.
The smallest of the main US islands besides Water Island, St. John is located about four miles east of Saint Thomas, the location of the territory's capital, Charlotte Amalie. It is four miles southwest of Tortola, part of the British Virgin Islands.
Since 1956, approximately 60% of the island is protected as Virgin Islands National Park, administered by the United States National Park Service. The economy is based on tourism.