United States

United States of America
Flag Great Seal
Motto: In God We Trust  (official) E Pluribus Unum  (traditional) (Latin: Out of Many, One)
Anthem: "The Star-Spangled Banner"
Capital		Washington, D.C. 38°53′N 77°01′W
Largest city		New York City
Official language(s)		None at federal level
National language		English (de facto)
Demonym		American
Government		Federal presidentialconstitutional republic
-	President	Barack Obama
-	Vice President	Joe Biden
-	Speaker of the House	John Boehner
-	Chief Justice	John Roberts
Legislature		Congress
-	Upper House	Senate
-	Lower House	House of Representatives
Independence from the Kingdom of Great Britain
-	Declared	July 4, 1776
-	Recognized	September 3, 1783
-	Current constitution	June 21, 1788
Area
-	Total	9,826,675 km2 (3rd/4th) 3,794,101 sq mi
-	Water (%)	6.76
Population
-	2010 census	308,745,538
-	Density	33.7/km2 87.4/sq mi
GDP (PPP)		2010 estimate
-	Total	$14.624 trillion
-	Per capita	$47,123
GDP (nominal)		2010 estimate
-	Total	$14.624 trillion (1st)
-	Per capita	$47,132 (9th)
Gini (2007)		45.0 (44th)
HDI (2010)		0.902 (very high) (4th)
Currency		United States dollar ($) (USD)
Time zone		(UTC−5 to −10)
-	Summer (DST)	(UTC−4 to −10)
Date formats		m/d/yy (AD)
Drives on the		right
Internet TLD		.us .gov .mil .edu
Calling code		+1
^ a. English is the official language of at least 28 states—some sources give a higher figure, based on differing definitions of "official".[5] English and Hawaiian are both official languages in the state of Hawaii. ^ b. English is the de facto language of American government and the sole language spoken at home by 80% of Americans age five and older. Spanish is the second most commonly spoken language. ^ c. Whether the United States or the People's Republic of China is larger is disputed. The figure given is from the U.S.Central Intelligence Agency's World Factbook. Other sources give smaller figures. All authoritative calculations of the country's size include only the 50 states and the District of Columbia, not the territories. ^ d. The population estimate includes people whose usual residence is in the fifty states and the District of Columbia, including noncitizens. It does not include either those living in the territories, amounting to more than 4 million U.S. citizens (most in Puerto Rico), or U.S. citizens living outside the United States.

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 statesand 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 3.79 million square miles (9.83 million km²) and with over 308 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 2010 GDP of $14.7 trillion (23% 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 Constitutionwas 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.

Through the 19th century, the United States displaced native tribes, acquired land from France, Spain, the United Kingdom, Mexico, and Russia, and annexed themRepublic of Texas and the Republic of Hawaii. Disputes between the agrarian South and industrial North over the expansion of the institution of slavery and states' rights 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.