Britain's American colonies broke with the mother country in 1776 and were recognized as the new nation of the United States of America following the Treaty of Paris in 1783. During the 19th and 20th centuries, 37 new states were added to the original 13 as the nation expanded across the North American continent and acquired a number of overseas possessions. The two most traumatic experiences in the nation's history were the Civil War (1861-65), in which a northern Union of states defeated a secessionist Confederacy of 11 southern slave states, and the Great Depression of the 1930s, an economic downturn during which about a quarter of the labor force lost its jobs. Buoyed by victories in World Wars I and II and the end of the Cold War in 1991, the US remains the world's most powerful nation state. Since the end of World War II, the economy has achieved relatively steady growth, low unemployment and inflation, and rapid advances in technology.

North America, bordering both the North Atlantic Ocean and the North Pacific Ocean, between Canada and Mexico

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; more than twice the size of the European Union

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

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

coal, copper, lead, molybdenum, phosphates, rare earth elements, uranium, bauxite, gold, iron, mercury, nickel, potash, silver, tungsten, zinc, petroleum, natural gas, timber

230,000 sq km (2003)

tsunamis; volcanoes; 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

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; limited natural freshwater resources in much of the western part of the country require careful management; desertification

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

white 79.96%, black 12.85%, Asian 4.43%, Amerindian and Alaska native 0.97%, native Hawaiian and other Pacific islander 0.18%, two or more races 1.61% (July 2007 estimate)

English 82.1%, Spanish 10.7%, other Indo-European 3.8%, Asian and Pacific island 2.7%, other 0.7% (2000 census)

Protestant 51.3%, Roman Catholic 23.9%, Mormon 1.7%, other Christian 1.6%, Jewish 1.7%, Buddhist 0.7%, Muslim 0.6%, other or unspecified 2.5%, unaffiliated 12.1%, none 4% (2007 est.)

313,847,465 (July 2012 est.)

13.68 births/1,000 population (2012 est.)

8.39 deaths/1,000 population (July 2012 est.)

3.62 migrant(s)/1,000 population (2012 est.)

New York-Newark 19.3 million; Los Angeles-Long Beach-Santa Ana 12.675 million; Chicago 9.134 million; Miami 5.699 million; WASHINGTON, D.C. (capital) 4.421 million (2009)

21 deaths/100,000 live births (2010)

2.06 children born/woman (2012 est.)

2.672 physicians/1,000 population (2004)

3.1 beds/1,000 population (2008)

1.2 million (2009 est.)

Constitution-based federal republic; strong democratic tradition

50 states and 1 district*; Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia*, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming

American Samoa, Baker Island, Guam, Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway Islands, Navassa Island, Northern Mariana Islands, Palmyra Atoll, Puerto Rico, Virgin Islands, Wake Island

4 July 1776 (declared); 3 September 1783 (recognized by Great Britain)

Independence Day, 4 July (1776)

17 September 1787, effective 4 March 1789

common law system based on English common law at the federal level; state legal systems based on common law except Louisiana, which is based on Napoleonic civil code; judicial review of legislative acts

withdrew acceptance of compulsory ICJ jurisdiction in 2005; withdrew acceptance of ICCt jurisdiction in 2002

18 years of age; universal

bicameral Congress consists of the Senate (100 seats, 2 members elected from each state by popular vote to serve six-year terms; one-third elected every two years) and the House of Representatives (435 seats; members directly elected by popular vote to serve two-year terms)

Supreme Court (nine justices; nominated by the president and confirmed with the advice and consent of the Senate; appointed to serve for life); United States Courts of Appeal; United States District Courts; State and County Courts

Democratic Party [Debbie Wasserman SCHULTZ]; Green Party; Libertarian Party [Mark HINKLE]; Republican Party [Reince PRIEBUS]

environmentalists; business groups; labor unions; churches; ethnic groups; political action committees or PAC; health groups; education groups; civic groups; youth groups; transportation groups; agricultural groups; veterans groups; women's groups; reform lobbies

ADB (nonregional member), AfDB (nonregional member), ANZUS, APEC, Arctic Council, ARF, ASEAN (dialogue partner), Australia Group, BIS, BSEC (observer), CBSS (observer), CD, CE (observer), CERN (observer), CICA (observer), CP, EAPC, EAS, EBRD, FAO, FATF, G-20, G-5, G-7, G-8, G-10, IADB, IAEA, IBRD, ICAO, ICC, ICRM, IDA, IEA, IFAD, IFC, IFRCS, IGAD (partners), IHO, ILO, IMF, IMO, IMSO, Interpol, IOC, IOM, ISO, ITSO, ITU, ITUC, MIGA, MINUSTAH, MONUSCO, NAFTA, NATO, NEA, NSG, OAS, OECD, OPCW, OSCE, Paris Club, PCA, PIF (partner), SAARC (observer), SELEC (observer), SPC, UN, UNCTAD, UNESCO, UNHCR, UNITAR, UNMIL, UNRWA, UNSC (permanent), UNTSO, UPU, WCO, WHO, WIPO, WMO, WTO, ZC

13 equal horizontal stripes of red (top and bottom) alternating with white; there is a blue rectangle in the upper hoist-side corner bearing 50 small, white, five-pointed stars arranged in nine offset horizontal rows of six stars (top and bottom) alternating with rows of five stars; the 50 stars represent the 50 states, the 13 stripes represent the 13 original colonies; the blue stands for loyalty, devotion, truth, justice, and friendship; red symbolizes courage, zeal, and fervency, while white denotes purity and rectitude of conduct; commonly referred to by its nickname of Old Glory

The US has the largest and most technologically powerful economy in the world, with a per capita GDP of $48,100. In this market-oriented economy, private individuals and business firms make most of the decisions, and the federal and state governments buy needed goods and services predominantly in the private marketplace. US business firms enjoy greater flexibility than their counterparts in Western Europe and Japan in decisions to expand capital plant, to lay off surplus workers, and to develop new products. At the same time, they face higher barriers to enter their rivals' home markets than foreign firms face entering US markets. US firms are at or near the forefront in technological advances, especially in computers and in medical, aerospace, and military equipment; their advantage has narrowed since the end of World War II. The onrush of technology largely explains the gradual development of a "two-tier labor market" in which those at the bottom lack the education and the professional/technical skills of those at the top and, more and more, fail to get comparable pay raises, health insurance coverage, and other benefits. Since 1975, practically all the gains in household income have gone to the top 20% of households. Since 1996, dividends and capital gains have grown faster than wages or any other category of after-tax income. Imported oil accounts for nearly 55% of US consumption. Oil prices doubled between 2001 and 2006, the year home prices peaked; higher gasoline prices ate into consumers' budgets and many individuals fell behind in their mortgage payments. Oil prices increased another 50% between 2006 and 2008. In 2008, soaring oil prices threatened inflation and caused a deterioration in the US merchandise trade deficit, which peaked at $840 billion. In 2009, with the global recession deepening, oil prices dropped 40% and the US trade deficit shrank, as US domestic demand declined, but in 2011 the trade deficit ramped back up to $803 billion, as oil prices climbed once more. The global economic downturn, the sub-prime mortgage crisis, investment bank failures, falling home prices, and tight credit pushed the United States into a recession by mid-2008. GDP contracted until the third quarter of 2009, making this the deepest and longest downturn since the Great Depression. To help stabilize financial markets, in October 2008 the US Congress established a $700 billion Troubled Asset Relief Program (TARP). The government used some of these funds to purchase equity in US banks and industrial corporations, much of which had been returned to the government by early 2011. In January 2009 the US Congress passed and President Barack OBAMA signed a bill providing an additional $787 billion fiscal stimulus to be used over 10 years - two-thirds on additional spending and one-third on tax cuts - to create jobs and to help the economy recover. In 2010 and 2011, the federal budget deficit reached nearly 9% of GDP; total government revenues from taxes and other sources are lower, as a percentage of GDP, than that of most other developed countries. The wars in Iraq and Afghanistan required major shifts in national resources from civilian to military purposes and contributed to the growth of the US budget deficit and public debt - through 2011, the direct costs of the wars totaled nearly $900 billion, according to US government figures. In March 2010, President OBAMA signed into law the Patient Protection and Affordable Care Act, a health insurance reform bill that will extend coverage to an additional 32 million American citizens by 2016, through private health insurance for the general population and Medicaid for the impoverished. Total spending on health care - public plus private - rose from 9.0% of GDP in 1980 to 17.9% in 2010. In July 2010, the president signed the DODD-FRANK Wall Street Reform and Consumer Protection Act, a law designed to promote financial stability by protecting consumers from financial abuses, ending taxpayer bailouts of financial firms, dealing with troubled banks that are "too big to fail," and improving accountability and transparency in the financial system - in particular, by requiring certain financial derivatives to be traded in markets that are subject to government regulation and oversight. Long-term problems include inadequate investment in deteriorating infrastructure, rapidly rising medical and pension costs of an aging population, sizable current account and budget deficits - including significant budget shortages for state governments - energy shortages, and stagnation of wages for lower-income families.

$15.29 trillion (2011 est.)

$15.03 trillion (2010 est.)

$14.58 trillion (2009 est.)

$15.09 trillion (2011 est.)

12.4% of GDP (2011 est.)

-8.6% of GDP (2011 est.)

67.7% of GDP (2011 est.)

62.8% of GDP (2010 est.)

0.5% (31 December 2010)

0.5% (31 December 2009)

3.25% (31 December 2011 est.)

3.25% (31 December 2010 est.)

$2.324 trillion (31 December 2011 est.)

$1.742 trillion (31 December 2010 est.)

$12.99 trillion (31 December 2011 est.)

$12.37 trillion (31 December 2009 est.)

$32.61 trillion (31 December 2009 est.)

$31.53 trillion (31 December 2008 est.)

$15.64 trillion (31 December 2011)

$17.14 trillion (31 December 2010)

$15.08 trillion (31 December 2009)

wheat, corn, other grains, fruits, vegetables, cotton; beef, pork, poultry, dairy products; fish; forest products

highly diversified, world leading, high-technology innovator, second largest industrial output in world; petroleum, steel, motor vehicles, aerospace, telecommunications, chemicals, electronics, food processing, consumer goods, lumber, mining

-$473.4 billion (2011 est.)

-$470.9 billion (2010 est.)

$1.497 trillion (2011 est.)

$1.289 trillion (2010 est.)

agricultural products (soybeans, fruit, corn) 9.2%, industrial supplies (organic chemicals) 26.8%, capital goods (transistors, aircraft, motor vehicle parts, computers, telecommunications equipment) 49.0%, consumer goods (automobiles, medicines) 15.0%

Canada 19%, Mexico 13.3%, China 7%, Japan 4.5% (2011)

$2.236 trillion (2011 est.)

$1.935 trillion (2010 est.)

agricultural products 4.9%, industrial supplies 32.9% (crude oil 8.2%), capital goods 30.4% (computers, telecommunications equipment, motor vehicle parts, office machines, electric power machinery), consumer goods 31.8% (automobiles, clothing, medicines, furniture, toys)

China 18.4%, Canada 14.2%, Mexico 11.7%, Japan 5.8%, Germany 4.4% (2011)

$148 billion (31 December 2011 est.)

$132.4 billion (31 December 2010 est.)

$14.71 trillion (30 June 2011)

$13.98 trillion (30 June 2010)

$2.571 trillion (31 December 2011 est.)

$2.343 trillion (31 December 2010 est.)

$4.314 trillion (31 December 2011 est.)

$3.908 trillion (31 December 2010 est.)

1 October - 30 September

4.12 trillion kWh (2010 est.)

3.889 trillion kWh (2010 est.)

19.41 billion kWh (2010 est.)

45.23 billion kWh (2010 est.)

1.025 billion kW (2010 est.)

75.5% of total installed capacity (2010 est.)

9.9% of total installed capacity (2010 est.)

7.7% of total installed capacity (2010 est.)

4.8% of total installed capacity (2010 est.)

9.023 million bbl/day (2011 est.)

43,800 bbl/day (2009 est.)

9.013 million bbl/day (2009 est.)

20.68 billion bbl (1 January 2012 est.)

17.88 million bbl/day (2009 est.)

18.84 million bbl/day (2011 est.)

1.876 million bbl/day (2009 est.)

1.255 million bbl/day (2009 est.)

651.3 billion cu m (2011 est.)

689.9 billion cu m (2011 est.)

42.67 billion cu m (2011 est.)

97.86 billion cu m (2011 est.)

7.716 trillion cu m (1 January 2009 est.)

5.61 billion Mt (2010 est.)

4 major terrestrial TV networks with affiliate stations throughout the country, plus cable and satellite networks, independent stations, and a limited public broadcasting sector that is largely supported by private grants; overall, thousands of TV stations broadcasting; multiple national radio networks with many affiliate stations; while most stations are commercial, National Public Radio (NPR) has a network of some 600 member stations; satellite radio available; overall, nearly 15,000 radio stations operating (2008)

498 million (2011); note - the US Internet total host count includes the following top level domain host addresses: .us, .com, .edu, .gov, .mil, .net, and .org

petroleum products 244,620 km; natural gas 548,665 km (2010)

41,009 km (19,312 km used for commerce; Saint Lawrence Seaway of 3,769 km, including the Saint Lawrence River of 3,058 km, is shared with Canada) (2012)

United States Armed Forces: US Army, US Navy (includes Marine Corps), US Air Force, US Coast Guard; note - Coast Guard administered in peacetime by the Department of Homeland Security, but in wartime reports to the Department of the Navy (2009)

18 years of age (17 years of age with parental consent) for male and female voluntary service; maximum enlistment age 42 (Army), 27 (Air Force), 34 (Navy), 28 (Marines); service obligation 8 years, including 2-5 years active duty (Army), 2 years active (Navy), 4 years active (Air Force, Marines) (2010)

4.06% of GDP (2005 est.)

the US has intensified domestic security measures and is collaborating closely with its neighbors, Canada and Mexico, to monitor and control legal and illegal personnel, transport, and commodities across the international borders; abundant rainfall in recent years along much of the Mexico-US border region has ameliorated periodically strained water-sharing arrangements; 1990 Maritime Boundary Agreement in the Bering Sea still awaits Russian Duma ratification; Canada and the United States dispute how to divide the Beaufort Sea and the status of the Northwest Passage but continue to work cooperatively to survey the Arctic continental shelf; The Bahamas and US have not been able to agree on a maritime boundary; US Naval Base at Guantanamo Bay is leased from Cuba and only mutual agreement or US abandonment of the area can terminate the lease; Haiti claims US-administered Navassa Island; US has made no territorial claim in Antarctica (but has reserved the right to do so) and does not recognize the claims of any other states; Marshall Islands claims Wake Island; Tokelau included American Samoa's Swains Island among the islands listed in its 2006 draft constitution

world's largest consumer of cocaine (shipped from Colombia through Mexico and the Caribbean), Colombian heroin, and Mexican heroin and marijuana; major consumer of ecstasy and Mexican methamphetamine; minor consumer of high-quality Southeast Asian heroin; illicit producer of cannabis, marijuana, depressants, stimulants, hallucinogens, and methamphetamine; money-laundering center