Guam; Chamorro: Guåhån), officially the Territory of Guam, is an island in the western Pacific Ocean and is an organised, unincorporated insular area of the United States. It is one of five U.S. territories with an established civilian government. The island's capital is Hagåtña (formerly Agana). Guam is the largest and southernmost of the Mariana Islands.
The Chamorros, Guam's indigenous inhabitants, first populated the island approximately 4,000 years ago. The island has a long history of European colonialism beginning in 1668 with the arrival of Spanish settlers including Padre San Vitores, a Catholic missionary. The island was taken over from Spain by the United States during the Spanish American War in 1898. As the largest island in Micronesia and the only American-held island in the region before World War II, Guam was occupied by the Japanese in December 1941, and was subject to fierce fighting when American troops recaptured the island in July 1944. Today, Guam's economy is mainly supported by tourism (primarily from Japan) and U.S. military bases.