What is Guam's relationship to the United States?

Guam is an unincorporated territory of the United States, under the Organic Act of Guam, which the U.S. Congress passed in 1950, granting citizenship to all Chamorros. Although Guamanians do not have the right to vote in national elections, they can vote in presidential primaries and send delegates to the national conventions of both the Democratic and Republican parties. Guam elects a delegate to the U.S. House of Representatives who has limited voting rights. The island also has a local government that includes a popularly elected governor and a unicameral legislature. The U.S. military has a significant presence on Guam, with about one-third of the island's land owned by the U.S. armed forces.

What is the climate like on Guam?

Guam has a pleasant tropical climate moderated by northeast trade winds and the north equatorial ocean current. Temperatures are fairly consistent year-round, ranging from 70 to 90 °F (20 to 30 °C). The island receives an average annual precipitation of about 95 inches (2,400 mm), with most rainfall occurring during the wet season from May or June through November. Guam's consistent climate is occasionally disrupted by destructive typhoons (tropical cyclones). Typhoon Tip, which passed south of Guam in 1979, dropped 9 inches (23 cm) of rain on the island. In 2002, another typhoon devastated Guam, leaving thousands homeless.

Who are the native people of Guam?

The native people of Guam are the Chamorros, who are believed to have come to the Mariana Islands from insular Southeast Asia around 1600 BCE. They are of Malayo-Indonesian descent with a mix of Spanish, Filipino, Mexican, and other European and Asian ancestries. The Chamorro language is still used in many homes, but English is the language of education and commerce. The word Chamorro comes from Chamorri , meaning "noble". Today, Chamorros and other Micronesians account for about half of Guam's population.

Why is Guam important for military and travel purposes?

Guam is strategically significant for the U.S. military due to its location and facilities. The island hosts multiple military installations , including Andersen Air Force Base and U.S. Naval facilities, with about one-third of Guam's land owned by the U.S. armed forces. These bases provide a vital foothold in the Western Pacific. Guam's international airport enhances its importance for travel, connecting the island to other Pacific destinations, Asia, Hawaii, and the continental United States. Tourism is a major economic driver, attracting over a million visitors annually.

How has Guam's history influenced its culture today?

Guam's culture is a mix of influences from its history, including its indigenous Chamorro roots and Spanish and American colonial periods. The Chamorro people's ancestors came from Southeast Asia around 1600 BCE. Spain claimed Guam in 1565, which led to cultural changes, including the adoption of Roman Catholicism. After the Spanish-American War in 1898, the U.S. took control of Guam. Today, Guam is culturally diverse, with communities from China, the Philippines, Korea, and other Asian countries, in addition to the native Chamorro population. The extended family remains the main social unit on Guam, and the Chamorro language is still spoken in many homes, though English is the official language. Traditional arts, music, and dance have seen a revival, and local holidays like Discovery Day are celebrated alongside U.S. national holidays.

Guam

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Images

Map of Guam showing major towns, roads, rivers, and physical features such as Mount Lamlam and Mount Bolanos. The island is surrounded by the Philippine Sea to the west and the Pacific Ocean to the east, with locations like Hagatna, Dededo, and Apra Harbor labeled. An inset map in the lower left shows Guam's location in the western Pacific.

Map of the western Pacific Ocean highlighting Guam, a U.S. territory, with an orange marker and label for Hagatna, its capital. Surrounding countries and territories, such as the Northern Mariana Islands, Federated States of Micronesia, Palau, Papua New Guinea, and others, are labeled, along with major island groups and political affiliations. The map provides geographic context for Guam's location in relation to the wider Pacific region.

Steep green cliffs at Amantes Point overlook a coastline with clear water, with the city of Tumon visible in the distance along the shore in Guam.

Population-density map of Pacific island countries and territories, with darker shading indicating more people per square kilometer. Naoero is the most densely populated, while many larger island groups, including Papua New Guinea, the Solomon Islands, Vanuatu, and French Polynesia, have lower densities.

At a Glance

Guam summary

Guam

island, Pacific Ocean

Written by

Dirk Anthony BallendorfAll

Fact-checked by

Britannica Editors

Last updated

Nov. 11, 2026 •History

News •

5 people rescued in South Pacific after months adrift at sea, 4 others missing • Nov. 3, 2026, 10:18 AM ET (CBS)

US Army activates air defense battalion in Guam amid N. Korean, Chinese missile threats: report • Oct. 23, 2026, 10:22 PM ET (Korea Herald)

Super Typhoon Champi Passes Near Guam, Bringing ‘Extremely Dangerous’ Winds • Oct. 17, 2026, 4:27 PM ET (New York Times)

A brewing Pacific storm could become one of the planet’s strongest this year • Oct. 15, 2026, 7:30 PM ET (Washington Post)

Guam, island and unincorporated territory of the United States in the North Pacific Ocean, the largest, most populous, and southernmost of the Mariana Islands. It lies about 5,800 miles (9,300 km) west of San Francisco and 1,600 miles (2,600 km) east of Manila.

Hagåtña (Agana) is the capital. Major settlements are Dededo, in the north-central part of the island, Machanao, in the north, and Apotgan, on the west coast.

Quick Facts

See article: flag of Guam

Head Of Government:: Governor: Lou Leon Guerrero

Capital:: Hagåtña (formerly Agana)

Population:: (2025 est.) 151,000

Currency Exchange Rate:: 1 US dollar equals 0.904 euro

Head Of State:: President of the United States: Donald Trump

Land

The island is sharply divided into a northern limestone plateau with a general elevation of about 500 feet (150 metres) and a higher area of volcanic hills to the south. The plateau is covered with a thick growth of jungle, while the volcanic hills support mainly sword grass. The hills rise to an elevation of more than 1,000 feet (300 metres); their lower slopes to the east (and also, in part, to the west) are covered with younger limestones, generally similar to those of the northern limestone plateau. The island rises to 1,332 feet (406 metres) at Mount Lamlam, in the southwest. To the southeast of Mount Lamlam is another major hill, Mount Bolanos (1,240 feet [378 metres]).

Guam has a pleasant tropical climate tempered by the northeast trade winds and the north equatorial ocean current that flows west across the Pacific. Temperatures range between approximately 70 and 90 °F (20 and 30 °C) and are fairly even throughout the year. Average annual precipitation is about 95 inches (2,400 mm), three-fourths of which falls in storms during the wet season, generally starting in May or June and lasting through November. The evenness of the climate is punctuated by destructive typhoons (tropical cyclones) that occur at irregular intervals.

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Palm trees, ferns, and other tropical plants abound. Many types of marine life and insects are also found. However, as a result of the accidental introduction in the 1940s of the brown tree snake, an invasive species from New Guinea, indigenous bird life on Guam has been devastated. At least a dozen bird species have become extinct, and several more are endangered. The abundant snakes have also caused numerous power outages by climbing poles and wires and crawling into transmission equipment, and they have killed small mammals.

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People

Native Guamanians, ethnically called Chamorros, are of basically Malayo-Indonesian descent with a considerable admixture of Spanish, Filipino, Mexican, and other European and Asian ancestries. Chamorros and other Micronesians constitute about half the population. Nearly one-third of the people are Asians, notably Filipinos and Koreans, and there is a small minority of people of European ancestry. About three-fourths of the people are Roman Catholic, and one-eighth are Protestant.

The Chamorro language is an Austronesian language that has, over time, come to incorporate many Spanish words. The word Chamorro is derived from Chamorri, or Chamoli, meaning “noble.” English and Chamorro are the official languages; although Chamorro is still used in many homes, English is the language of education and commerce. Because of the number of tourists and investors from Japan, Japanese is increasingly also used.

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The island’s rate of natural increase, although about average for the region, is high compared with that of the United States, partly because of a low death rate. There are large numbers of migrants from the Philippines and South Korea, as well as from neighbouring states such as the Federated States of Micronesia, Palau, and the Republic of the Marshall Islands.

Economy

The development of Guam into an important U.S. military base brought about profound changes in the island’s agricultural patterns after World War II. Foodstuffs were imported in increasing amounts at the expense of local cultivation, and Guam now imports most of its food.

F-22 RaptorA pair of F-22 Raptors patrolling the Pacific Ocean during a deployment of the 90th Expeditionary Fighter Squadron to Andersen Air Force Base, Guam.

The U.S. armed forces are represented at multiple military facilities on Guam. Andersen Air Force Base and its annexes are concentrated at the northern end of the island. U.S. Navy facilities, located around the island, include a naval air station, a naval base with a ship repair yard, communications centres, and a hospital. Work at the military facilities has drawn many islanders away from their former lives of subsistence agriculture and fishing.

Tourism is the most prominent component of the economy, with more than a million visitors arriving per year. There are several luxury hotels along Tumon Bay, which has been highly developed as a tourist area. An international airport links Guam with other Pacific islands, Asia, and Hawaii and the continental United States.

Poultry farming, garment-finishing plants, and oil refining are important earners. Guam is a duty-free port, and this status has attracted a number of small manufacturing companies from countries in Asia and has also prompted some immigration. Major imports—mostly from the United States and Japan—include food products, motor vehicles and parts, and shoes and other leather products. The leading exports are motor vehicles and parts, fish and other food products, scrap metal, and tobacco products. Finland, Japan, and the Federated States of Micronesia are the main export destinations.

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