Geography of Guam

This article describes the geography of the United States territory of Guam.

Location

Oceania, island in the North Pacific Ocean, about a quarter of the way from the Philippines to Hawaii, United States

Geographic coordinates

13°26′31″N 144°46′35″E

Coastline

125.5 km (78.0 mi)

Maritime claims

• Territorial sea: 12 nmi (22 km)
• Exclusive economic zone: 200 nautical miles (370 kilometres)
• The southern maritime boundary of Guam forms a border with the Federated States of Micronesia, and the northern maritime boundary forms a border with the Commonwealth of the Northern Marianas Islands.

Climate

Tropical marine; generally warm and humid, moderated by northeast trade winds; dry season from January to June, wet season from July to December; little seasonal temperature variation.

Terrain

Volcanic origin, surrounded by coral reefs; relatively flat coralline limestone plateau (source of most freshwater), with steep coastal cliffs and narrow coastal plains in north, low-rising hills in center, mountains in south. Soils are mostly silty clay or clay and may be gray, black, brown or reddish brown; acidity and depth vary.[2]

Elevation extremes

• Lowest point: Pacific Ocean, 0 metres (0 feet)[3]
• Highest points:
  1. Mount Lamlam, 406 meters (1,332 ft)[3]
  2. Mount Jumullong Manglo, 391 meters (1,283 ft)
  3. Mount Bolanos, 368 meters (1,207 ft)

Natural resources

Commercial fishing (mostly servicing and unloading of longline fleets and commercial vessels), recreational fishing of Indo-Pacific Blue Marlin (Makaira mazara), Wahoo (Acanthocybium solandri), Mahi-mahi (Coryphaena hippurus), Yellowfin tuna (Thunnus albacares), and deepwater reef fish, tourism (especially from Japan but increasingly from China and South Korea).

Land use

• Arable land: 1.85%
• Permanent crops: 16.67%
• Other: 81.48% (2012 est.)

Irrigated land

2 ^km2

Natural hazards

Frequent squalls during wet season; relatively rare, but potentially very destructive typhoons (typhoons are possible in any season but most common from August through December)

Environment - current issues

Extirpation of native bird population by the rapid proliferation of the Brown tree snake (Boiga irregularis), an exotic species. Island also supports feral populations of introduced deer, Pigs (Sus scrofa) and Carabao (Bubalus bubalis carabanesis).

Geography - note

Largest and southernmost island in the Mariana Islands archipelago; strategic location in western North Pacific Ocean.

Guam

Native name: Guåhån
Map of Guam (See detailed map)
Geography
Location	Pacific Ocean
Coordinates	13°26′31″N 144°46′35″E
Archipelago	Mariana Islands
Area	544 km2 (210 sq mi)
Length	51 km (31.7 mi)
Width	15 km (9.3 mi)
Highest elevation	406 m (1332 ft)
Highest point	Mount Lamlam
Administration
United States
Territory	Guam
Largest settlement	Dededo (pop. 46,000)
Demographics
Population	167,358 [1] (July 2017 est.)
Pop. density	320.44/km2 (829.94/sq mi)
Ethnic groups	Native Chamorros (57%), Filipino (25.5%), White (10%), Chinese, Japanese and Korean ancestry

Guam population density and low elevation coastal zones. Guam is especially vulnerable to sea level rise.