Geography of Guam

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Native name:
Map of Guam (See detailed map)
Map of USA GU.png
LocationPacific Ocean
Coordinates13°26′31″N 144°46′35″E / 13.44194°N 144.77639°E / 13.44194; 144.77639Coordinates: 13°26′31″N 144°46′35″E / 13.44194°N 144.77639°E / 13.44194; 144.77639
ArchipelagoMariana Islands
Area544 km2 (210 sq mi)
Length51 km (31.7 mi)
Width15 km (9.3 mi)
Highest elevation406 m (1,332 ft)
Highest pointMount Lamlam
Largest settlementDededo (pop. 46,000)
Population167,358 [1] (July 2017 est.)
Pop. density320.44 /km2 (829.94 /sq mi)
Ethnic groupsNative Chamorros (57%), Filipino (25.5%), White (10%), Chinese, Japanese and Korean ancestry
Pass of the ISS over Mongolia, looking out west towards the Pacific Ocean, China, and Japan. As the video progresses, you can see major cities along the coast and the Japanese islands on the Philippine Sea. The island of Guam can be seen further down the pass into the Philippine Sea, and the pass ends just to the east of New Zealand. A lightning storm can be seen as light pulses near the end of the video.

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

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 / 13.44194°N 144.77639°E / 13.44194; 144.77639
Map references
  • Total: 544 km²
  • Land: 544 km²
  • Water: 0 km²
Area (comparative)
Three times the size of Washington, D.C.
Land boundaries
Approximately 30 miles (48 km) long and 9 miles (14 km) wide, narrowing to 4 miles (6.4 km) at the center.
125.5 km (78.0 mi)
Maritime claims
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.
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
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.

Extreme points[edit]

This is a list of the extreme points of Guam, the points that are farther north, south, east or west than any other location.


  1. ^ The World Factbook: Guam CIA. Retrieved on October 18, 2017.
  2. ^ https://casoilresource.lawr.ucdavis.edu/gmap/
  3. ^ a b "Elevations and Distances in the United States". U.S. Geological Survey. 29 April 2005. Retrieved November 9, 2006.