The United States of America (also referred to as the United States, the U.S., the USA, or America) is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C., the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south. The state of Alaska is in the northwest of the continent, with Canada to the east and Russia to the west across the Bering Strait. The state of Hawaii is an archipelago in the mid-Pacific. The country also possesses several territories in the Caribbean and Pacific.
At 3.719 million square miles and with 309 million people, the United States is the third or fourth largest country by total area, and the third largest both by land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The U.S. economy is the world's largest national economy, with an estimated 2009 GDP of $14.3 trillion (24% of nominal global GDP and 20% of global GDP at purchasing power parity).
Indigenous peoples of Asian origin have inhabited what is now the mainland United States for many thousands of years. This Native American population was greatly reduced by disease and warfare after European contact. The United States was founded by thirteen British colonies located along the Atlantic seaboard. On July 4, 1776, they issued the Declaration of Independence, which proclaimed their right to self-determination and their establishment of a cooperative union. The rebellious states defeated the British Empire in the American Revolution, the first successful colonial war of independence. The current United States Constitution was adopted on September 17, 1787; its ratification the following year made the states part of a single republic with a strong federal government. The Bill of Rights, comprising ten constitutional amendments guaranteeing many fundamental civil rights and freedoms, was ratified in 1791.
In the 19th century, the United States acquired land from France, Spain, the United Kingdom, Mexico, and Russia, and annexed the Republic of Texas and the Republic of Hawaii. Disputes between the agrarian South and industrial North over states' rights and the expansion of the institution of slavery provoked the American Civil War of the 1860s. The North's victory prevented a permanent split of the country and led to the end of legal slavery in the United States. By the 1870s, the national economy was the world's largest. The Spanish-American War and World War I confirmed the country's status as a military power. It emerged from World War II as the first country with nuclear weapons and a permanent member of the United Nations Security Council. The end of the Cold War and the dissolution of the Soviet Union left the United States as the sole superpower. The country accounts for 43% of global military spending and is a leading economic, political, and cultural force in the world.
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Population 4,780,000
Capital Montgomery
Land Area 50,700 mi2
Directory Listings 439
Population 686,293
Capital Juneau
Land Area 572,000 mi2
Directory Listings 106
Population 6,392,000
Capital Phoenix
Land Area 114,000 mi2
Directory Listings 204
Population 2,855,000
Capital Little Rock
Land Area 52,100 mi2
Directory Listings 197
Population 37,250,000
Capital Sacramento
Land Area 156,000 mi2
Directory Listings 504
Population 4,939,000
Capital Denver
Land Area 104,000 mi2
Directory Listings 211
Population 3,574,000
Capital Hartford
Land Area 4,840 mi2
Directory Listings 115
Population 873,092
Capital Dover
Land Area 1,950 mi2
Directory Listings 43
Population 591,833
Capital Washington
Land Area 61 mi2
Directory Listings 11
Population 18,800,000
Capital Tallahassee
Land Area 53,900 mi2
Directory Listings 774
Population 9,686,000
Capital Atlanta
Land Area 57,900 mi2
Directory Listings 848
Population 1,360,000
Capital Honolulu
Land Area 6,420 mi2
Directory Listings 53
Population 1,524,000
Capital Boise
Land Area 82,700 mi2
Directory Listings 76
Population 12,830,000
Capital Springfield
Land Area 55,600 mi2
Directory Listings 444
Population 6,377,000
Capital Indianapolis
Land Area 35,900 mi2
Directory Listings 448
Population 3,003,000
Capital Des Moines
Land Area 55,900 mi2
Directory Listings 153
Population 2,853,000
Capital Topeka
Land Area 81,800 mi2
Directory Listings 197
Population 4,269,000
Capital Frankfort
Land Area 39,700 mi2
Directory Listings 476
Population 4,533,000
Capital Baton Rouge
Land Area 43,600 mi2
Directory Listings 270
Population 1,328,000
Capital Augusta
Land Area 30,900 mi2
Directory Listings 139
Population 5,634,000
Capital Annapolis
Land Area 9,770 mi2
Directory Listings 178
Population 6,548,000
Capital Boston
Land Area 7,840 mi2
Directory Listings 143
Population 9,884,000
Capital Lansing
Land Area 56,800 mi2
Directory Listings 553
Population 5,220,000
Capital Saint Paul
Land Area 79,600 mi2
Directory Listings 121
Population 2,967,000
Capital Jackson
Land Area 46,900 mi2
Directory Listings 297
Population 5,912,000
Capital Jefferson City
Land Area 68,900 mi2
Directory Listings 320
Population 989,415
Capital Helena
Land Area 146,000 mi2
Directory Listings 67
Population 1,783,000
Capital Lincoln
Land Area 76,900 mi2
Directory Listings 65
Population 2,600,000
Capital Carson City
Land Area 110,000 mi2
Directory Listings 46
Population 1,316,000
Capital Concord
Land Area 8,970 mi2
Directory Listings 65
Population 8,683,000
Capital Trenton
Land Area 7,420 mi2
Directory Listings 154
Population 2,590,000
Capital Santa Fe
Land Area 121,000 mi2
Directory Listings 109
Population 19,380,000
Capital Albany
Land Area 47,200 mi2
Directory Listings 393
Population 9,535,000
Capital Raleigh
Land Area 48,700 mi2
Directory Listings 1,035
Population 672,591
Capital Bismarck
Land Area 69,000 mi2
Directory Listings 32
Population 11,490,000
Capital Columbus
Land Area 40,900 mi2
Directory Listings 683
Population 3,751,000
Capital Oklahoma City
Land Area 68,700 mi2
Directory Listings 206
Population 3,831,000
Capital Salem
Land Area 96,000 mi2
Directory Listings 108
Population 12,450,000
Capital Harrisburg
Land Area 44,800 mi2
Directory Listings 489
Population 1,053,000
Capital Providence
Land Area 1,040 mi2
Directory Listings 40
Population 4,625,000
Capital Columbia
Land Area 30,100 mi2
Directory Listings 442
Population 814,180
Capital Pierre
Land Area 75,900 mi2
Directory Listings 41
Population 6,346,000
Capital Nashville
Land Area 41,200 mi2
Directory Listings 777
Population 25,150,000
Capital Austin
Land Area 262,000 mi2
Directory Listings 875
Population 2,764,000
Capital Salt Lake City
Land Area 82,100 mi2
Directory Listings 58
Population 625,741
Capital Montpelier
Land Area 9,250 mi2
Directory Listings 33
Population 8,001,000
Capital Richmond
Land Area 39,600 mi2
Directory Listings 546
Population 6,725,000
Capital Olympia
Land Area 66,544 mi2
Directory Listings 199
Population 1,814,000
Capital Charleston
Land Area 24,100 mi2
Directory Listings 305
Population 5,628,000
Capital Madison
Land Area 54,300 mi2
Directory Listings 218
Population 563,626
Capital Cheyenne
Land Area 97,100 mi2
Directory Listings 53