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 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 people, first populated the island approximately 4,000 years ago.   The island has a long history of European colonialism. First discovered by Europeans on March 6, 1521, by Ferdinand Magellan, the first colony was established in 1668 by Spain with the arrival of settlers including Padre San Vitores, a Catholic missionary. The island was controlled by Spain until 1898, when it was surrendered to the United States as part of the Treaty of Paris following the Spanish-American War.