Geography of Guam

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	541.3 km2 (209 sq mi)
Length	51 km (31.7 mi)
Width	15 km (9.3 mi)
Highest elevation	406 m (1,332 ft)
Highest point	Mount Lamlam
Country
United States
Territory of the United States	Guam
Largest city	Dededo (pop. 46,000)
Demographics
Population	173,456 (as of 2007)
Density	320.44 /km2 (829.94 /sq mi)
Ethnic groups	Native 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.

Location

Oceania, island in the North Pacific Ocean, about a quarter of the way from the Philippines to Hawaii, U.S.A.

Geographic coordinates

13°26′31″N 144°46′35″E

Map references

Oceania

Area

• Total: 541.3 km²
• Land: 541.3 km²
• Water: 0 km²

Area (comparative)

Three times the size of Washington, D.C.

Land boundaries

Approximately 30 miles (51 km) long and 9 miles (15 km) wide, narrowing to 4 miles (7 km) at the center.

Coastline

125.5 km (78.0 mi)

Maritime claims

• Exclusive economic zone: 200 nm (370.4 km)
• Territorial sea: 12 nm (22.224 km)
• 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

Elevation extremes

• Lowest point: Pacific Ocean, 0 metres (0 ft)
• Highest points:
  1. Mount Lamlam, 406 meters (1,332 ft)
  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: 11%
• Permanent crops: 11%
• Permanent pastures: 15%
• Forests and woodland: 18%
• Other: 45% (1993 est.)

Irrigated land

N/A 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

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

• Northernmost point – Ritidian Point
• Easternmost point – Pati Point
• Southernmost point – Cocos Island
• Southernmost point (mainland) – Aga Point
• Westernmost point – Orote Point