GuamThe following outline is provided as an overview of and topical guide to Guam: Guam – organized, unincorporated territory of the United States of America that comprises the island of Guam in the western North Pacific Ocean. 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. Discovered by the Spanish expedition of Ferdinand Magellan in 1521, the island has a long history of European colonialism beginning in the 16th century, and especially in 1668 with the arrival of Spanish settlers including Padre San Vitores, a Catholic missionary. Guam and the res