Guam (Chamorro: Guåhan), officially the Territory of Guam, is an island in the Western Pacific Ocean and is an organized unincorporated territory of the United States. It is one of five U.S. territories with established civilian government. The Chamorros, Guam's indigenous inhabitants, first populated the island approximately 4,000 years ago. Guam is the largest and southernmost of the Mariana Islands. The island's capital is Hagåtña (formerly Agana). Guam's economy is mainly supported by tourism (primarily from Japan) and U.S. military bases.