Geography United States

Location:

North America, bordering both the North Atlantic Ocean and the

North Pacific Ocean, between Canada and Mexico

Geographic coordinates:

38 00 N, 97 00 W

Map references:

North America

Area:

total: 9,629,091 sq km

land: 9,158,960 sq km

water: 470,131 sq km

note: includes only the 50 states and District of Columbia

Area - comparative:

about half the size of Russia; about three-tenths the size of

Africa; about half the size of South America (or slightly larger

than Brazil); slightly larger than China; about two and a half times

the size of Western Europe

Land boundaries:

total: 12,034 km

border countries: Canada 8,893 km (including 2,477 km with Alaska),

Mexico 3,141 km

note: US Naval Base at Guantanamo Bay, Cuba is leased by the US and

thus remains part of Cuba; the base boundary is 29 km

Coastline:

19,924 km

Maritime claims:

contiguous zone: 24 NM

continental shelf: not specified

exclusive economic zone: 200 NM

territorial sea: 12 NM

Climate:

mostly temperate, but tropical in Hawaii and Florida, arctic in

Alaska, semiarid in the great plains west of the Mississippi River,

and arid in the Great Basin of the southwest; low winter

temperatures in the northwest are ameliorated occasionally in

January and February by warm chinook winds from the eastern slopes

of the Rocky Mountains

Terrain:

vast central plain, mountains in west, hills and low mountains in

east; rugged mountains and broad river valleys in Alaska; rugged,

volcanic topography in Hawaii

Elevation extremes:

lowest point: Death Valley -86 m

highest point: Mount McKinley 6,194 m

Natural resources:

coal, copper, lead, molybdenum, phosphates, uranium, bauxite, gold,

iron, mercury, nickel, potash, silver, tungsten, zinc, petroleum,

natural gas, timber

Land use:

arable land: 19.32%

other: 80.46% (1998 est.)

permanent crops: 0.22%

Irrigated land:

214,000 sq km (1998 est.)

Natural hazards:

tsunamis, volcanoes, and earthquake activity around Pacific Basin;

hurricanes along the Atlantic and Gulf of Mexico coasts; tornadoes

in the midwest and southeast; mud slides in California; forest fires

in the west; flooding; permafrost in northern Alaska, a major

impediment to development

Environment - current issues:

air pollution resulting in acid rain in both the US and Canada; the

US is the largest single emitter of carbon dioxide from the burning

of fossil fuels; water pollution from runoff of pesticides and

fertilizers; very limited natural fresh water resources in much of

the western part of the country require careful management;

desertification

Environment - international agreements:

party to: Air Pollution, Air Pollution-Nitrogen Oxides,

Antarctic-Environmental Protocol, Antarctic-Marine Living Resources,

Antarctic Seals, Antarctic Treaty, Climate Change, Desertification,

Endangered Species, Environmental Modification, Marine Dumping,

Marine Life Conservation, Nuclear Test Ban, Ozone Layer Protection,

Ship Pollution, Tropical Timber 83, Tropical Timber 94, Wetlands,

Whaling

signed, but not ratified: Air Pollution-Persistent Organic

Pollutants, Air Pollution-Volatile Organic Compounds, Biodiversity,

Climate Change-Kyoto Protocol, Hazardous Wastes

Geography - note:

world's third-largest country by size (after Russia and Canada) and

by population (after China and India); Mt. McKinley is highest point

in North America and Death Valley the lowest point on the continent

The 2003 CIA World Factbook · 第 2554 / 3264 题