Guam — map and facts

About Guam

Guam is an unincorporated territory of the United States located in the western Pacific Ocean, the largest and southernmost island in the Mariana Islands archipelago. Its capital is Hagåtña, though the largest city is Dededo. The island has a population of approximately 153,000 people, predominantly of Chamorro descent alongside Filipino, other Asian, and American communities. Guam is governed under the Organic Act of Guam (1950), which granted residents U.S. citizenship, though they cannot vote in presidential elections. The island functions with a governor, legislature, and delegate to the U.S. House of Representatives (non-voting). The economy relies heavily on tourism—primarily from Japan, South Korea, and other East Asian countries—as well as a substantial U.S. military presence, with bases covering roughly a quarter of the island. Chamorro culture, language, and traditions remain central to local identity despite centuries of colonial influence.

Geography and Landscape

Guam covers approximately 541 square kilometers, making it the largest island in Micronesia. The island is roughly 48 kilometers long and between 6 and 19 kilometers wide. The northern portion consists of a relatively flat limestone plateau, while the southern half features rugged volcanic hills, river valleys, and the island's highest point, Mount Lamlam, at 406 meters. The western coast is lined with a fringing coral reef that shelters calm, clear lagoons—most famously Tumon Bay, the center of the tourism industry. The eastern coastline faces the open Pacific and is more exposed. Guam has a tropical marine climate with a wet season from July through November and a dry season from December through June. Typhoons are a recurring hazard. The island is surrounded by remarkably deep ocean, lying just west of the Mariana Trench, the deepest point on Earth.

History

Guam has been inhabited by the Chamorro people for at least 3,500 years. Spanish explorer Ferdinand Magellan arrived in 1521, and Spain formally colonized the island from 1668, introducing Catholicism and suppressing indigenous culture through a series of devastating wars and epidemics that drastically reduced the Chamorro population. Guam remained a Spanish colony for over two centuries, serving as a resupply stop on trans-Pacific galleon routes. Following Spain's defeat in the Spanish-American War, Guam was ceded to the United States in 1898 under the Treaty of Paris. During World War II, Japan occupied Guam from December 1941 until American forces liberated it in July–August 1944 after fierce fighting. The postwar period brought U.S. citizenship and greater civil governance. Questions of political status—including the possibility of greater autonomy or independence—continue to be discussed by Chamorro advocates and the broader community.