|United States of America|
|Anthem: “The Star-Spangled Banner”
The United States and its territories
|Largest city||New York City
|Official languages||None at federal level[fn 1]|
|National language||English[fn 2]|
|Ethnic groups||By race:
0.2% Pacific Islander
17.6% Hispanic or Latino
82.4% non-Hispanic or Latino
1.8% other faiths
|Government||Federal presidentialconstitutional republic|
|House of Representatives|
|July 4, 1776|
|March 1, 1781|
|September 3, 1783|
|June 21, 1788|
|March 24, 1976|
• Total area
|3,796,742 sq mi (9,833,520 km2)[fn 3](3rd/4th)|
• Water (%)
• Total land area
|3,531,905 sq mi (9,147,590 km2)|
• 2017 estimate
• 2010 census
|90.6/sq mi (35.0/km2) (180th)|
|GDP (PPP)||2016 estimate|
|$18.558 trillion (2nd)|
• Per capita
|GDP (nominal)||2016 estimate|
|$18.558 trillion (1st)|
• Per capita
|HDI (2015)|| 0.920
very high · 10th
|Currency||United States dollar ($) (USD)|
|Time zone||(UTC−4 to −12, +10, +11)|
• Summer (DST)
|(UTC−4 to −10[fn 4])|
|Drives on the||right[fn 5]|
|ISO 3166 code||US|
|Internet TLD||.us .gov .mil .edu|
The United States of America (USA), commonly referred to as the United States (U.S.) or America, is a constitutional federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions.[fn 6] Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The state of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea. Nine time zones are covered. The geography, climate and wildlife of the country are extremely diverse.
At 3.8 million square miles (9.8 million km2) and with over 324 million people, the United States is the world’s third- or fourth-largest country by total area,[fn 7] third-largest by land area, and the third-most populous. It is one of the world’s most ethnically diverse and multicultural nations, and is home to the world’s largest immigrant population. The capital is Washington, D.C., and the largest city is New York City; nine other major metropolitan areas—each with at least 4.5 million inhabitants and the largest having more than 13 million people—are Los Angeles, Chicago, Dallas, Houston, Philadelphia, Miami, Atlanta, Boston, and San Francisco.
Paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century. The United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the colonies following the Seven Years’ War led to the American Revolution, which began in 1775. On July 4, 1776, during the course of the American Revolutionary War, the colonies unanimously adopted the Declaration of Independence. The war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, adopted in 1781, were felt to have provided inadequate federal powers. The first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties.
The United States embarked on a vigorous expansion across North America throughout the 19th century, displacing American Indian tribes, acquiring new territories, and gradually admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the American Civil War led to the end of legal slavery in the country. By the end of that century, the United States extended into the Pacific Ocean, and its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country’s status as a global military power. The United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, and a permanent member of the United Nations Security Council. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the world’s sole superpower. The U.S. is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), and other international organizations.
The United States is a highly developed country, with the world’s largest economy by nominal GDP and second-largest economy by PPP. It ranks highly in several measures of socioeconomic performance, including average wage, human development, per capita GDP, and productivity per person. While the U.S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the manufacturing sector remains the second-largest in the world. Though its population is only 4.3% of the world total, the United States accounts for nearly a quarter of world GDP and over a third of global military spending, making it the world’s foremost economic and military power. The United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations.
In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere “America” after the Italian explorer and cartographer Amerigo Vespucci (Latin: Americus Vespucius). The first documentary evidence of the phrase “United States of America” is from a letter dated January 2, 1776, written by Stephen Moylan, Esq., George Washington‘s aide-de-camp and Muster-Master General of the Continental Army. Addressed to Lt. Col. Joseph Reed, Moylan expressed his wish to carry the “full and ample powers of the United States of America” to Spain to assist in the revolutionary war effort.
The first known publication of the phrase “United States of America” was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared “The name of this Confederation shall be the ‘United States of America.'” The final version of the Articles sent to the states for ratification in late 1777 contains the sentence “The Stile of this Confederacy shall be ‘The United States of America'”. In June 1776, Thomas Jefferson wrote the phrase “UNITED STATES OF AMERICA” in all capitalized letters in the headline of his “original Rough draught” of the Declaration of Independence. This draft of the document did not surface until June 21, 1776, and it is unclear whether it was written before or after Dickinson used the term in his June 17 draft of the Articles of Confederation. In the final Fourth of July version of the Declaration, the title was changed to read, “The unanimous Declaration of the thirteen united States of America”. The preamble of the Constitution states “…establish this Constitution for the United States of America.”
The short form “United States” is also standard. Other common forms are the “U.S.”, the “USA”, and “America”. Colloquial names are the “U.S. of A.” and, internationally, the “States”. “Columbia“, a name popular in poetry and songs of the late 18th century, derives its origin from Christopher Columbus; it appears in the name “District of Columbia“. In non-English languages, the name is frequently the translation of either the “United States” or “United States of America”, and colloquially as “America”. In addition, an abbreviation (e.g. USA) is sometimes used.
The phrase “United States” was originally plural, a description of a collection of independent states—e.g., “the United States are”—including in the Thirteenth Amendment to the United States Constitution, ratified in 1865. The singular form—e.g., “the United States is”—became popular after the end of the American Civil War. The singular form is now standard; the plural form is retained in the idiom “these United States”. The difference is more significant than usage; it is a difference between a collection of states and a unit.
A citizen of the United States is an “American“. “United States”, “American” and “U.S.” refer to the country adjectivally (“American values”, “U.S. forces”). In English, the word “American” rarely refers to topics or subjects not connected with the United States.
The first inhabitants of North America migrated from Siberia by way of the Bering land bridge and arrived at least 15,000 years ago, though increasing evidence suggests an even earlier arrival. Some, such as the pre-Columbian Mississippian culture, developed advanced agriculture, grand architecture, and state-level societies. After the Spanish conquistadors made the first contacts, the native population declined for various reasons, primarily from diseases such as smallpox and measles. Violence was not a significant factor in the overall decline among Native Americans, though conflict among themselves and with Europeans affected specific tribes and various colonial settlements. In the Hawaiian Islands, the earliest indigenous inhabitants arrived around 1 AD from Polynesia. Europeans under the British explorer Captain James Cook arrived in the Hawaiian Islands in 1778.
In the early days of colonization, many European settlers were subject to food shortages, disease, and attacks from Native Americans. Native Americans were also often at war with neighboring tribes and allied with Europeans in their colonial wars. At the same time, however, many natives and settlers came to depend on each other. Settlers traded for food and animal pelts, natives for guns, ammunition and other European wares. Natives taught many settlers where, when and how to cultivate corn, beans and squash. European missionaries and others felt it was important to “civilize” the Native Americans and urged them to adopt European agricultural techniques and lifestyles.
After Spain sent Columbus on his first voyage to the New World in 1492, other explorers followed. The Spanish set up small settlements in New Mexico and Florida. France had several small settlements along the Mississippi River. Successful English settlement on the eastern coast of North America began with the Virginia Colony in 1607 at Jamestown and the Pilgrims’ Plymouth Colony in 1620. Early experiments in communal living failed until the introduction of private farm holdings. Many settlers were dissenting Christian groups who came seeking religious freedom. The continent’s first elected legislative assembly, Virginia’s House of Burgesses created in 1619, and the Mayflower Compact, signed by the Pilgrims before disembarking, established precedents for the pattern of representative self-government and constitutionalism that would develop throughout the American colonies.
Most settlers in every colony were small farmers, but other industries developed within a few decades as varied as the settlements. Cash crops included tobacco, rice and wheat. Extraction industries grew up in furs, fishing and lumber. Manufacturers produced rum and ships, and by the late colonial period Americans were producing one-seventh of the world’s iron supply. Cities eventually dotted the coast to support local economies and serve as trade hubs. English colonists were supplemented by waves of Scotch-Irish and other groups. As coastal land grew more expensive freed indentured servants pushed further west.
Slave cultivation of cash crops began with the Spanish in the 1500s, and was adopted by the English, but life expectancy was much higher in North America because of less disease and better food and treatment, leading to a rapid increase in the numbers of slaves. Colonial society was largely divided over the religious and moral implications of slavery and colonies passed acts for and against the practice. But by the turn of the 18th century, African slaves were replacing indentured servants for cash crop labor, especially in southern regions.
With the British colonization of Georgia in 1732, the 13 colonies that would become the United States of America were established. All had local governments with elections open to most free men, with a growing devotion to the ancient rights of Englishmen and a sense of self-government stimulating support for republicanism. With extremely high birth rates, low death rates, and steady settlement, the colonial population grew rapidly. Relatively small Native American populations were eclipsed. The Christian revivalist movement of the 1730s and 1740s known as the Great Awakening fueled interest in both religion and religious liberty.
During the Seven Years’ War (also known as the French and Indian War), British forces seized Canada from the French, but the francophone population remained politically isolated from the southern colonies. Excluding the Native Americans, who were being conquered and displaced, those 13 colonies had a population of over 2.1 million in 1770, about one-third that of Britain. Despite continuing new arrivals, the rate of natural increase was such that by the 1770s only a small minority of Americans had been born overseas. The colonies’ distance from Britain had allowed the development of self-government, but their success motivated monarchs to periodically seek to reassert royal authority.
The American Revolutionary War was the first successful colonial war of independence against a European power. Americans had developed an ideology of “republicanism” asserting that government rested on the will of the people as expressed in their local legislatures. They demanded their rights as Englishmen and “no taxation without representation”. The British insisted on administering the empire through Parliament, and the conflict escalated into war.
Following the passage of the Lee Resolution, on July 2, 1776, which was the actual vote for independence, the Second Continental Congress adopted the Declaration of Independence on July 4, which proclaimed, in a long preamble, that humanity is created equal in their unalienable rights and that those rights were not being protected by Great Britain, and declared, in the words of the resolution, that the Thirteen Colonies were independent states and had no allegiance to the British crown in the United States. The fourth day of July is celebrated annually as Independence Day. In 1777, the Articles of Confederation established a weak government that operated until 1789.
Britain recognized the independence of the United States following their defeat at Yorktown in 1781. In the peace treaty of 1783, American sovereignty was recognized from the Atlantic coast west to the Mississippi River. Nationalists led the Philadelphia Convention of 1787 in writing the United States Constitution, ratified in state conventions in 1788. The federal government was reorganized into three branches, on the principle of creating salutary checks and balances, in 1789. George Washington, who had led the revolutionary army to victory, was the first president elected under the new constitution. The Bill of Rights, forbidding federal restriction of personal freedoms and guaranteeing a range of legal protections, was adopted in 1791.
Although the federal government criminalized the international slave trade in 1808, after 1820, cultivation of the highly profitable cotton crop exploded in the Deep South, and along with it, the slave population. The Second Great Awakening, especially 1800–1840, converted millions to evangelical Protestantism. In the North, it energized multiple social reform movements, including abolitionism; in the South, Methodists and Baptists proselytized among slave populations.
Americans’ eagerness to expand westward prompted a long series of American Indian Wars. The Louisiana Purchase of French-claimed territory in 1803 almost doubled the nation’s area. The War of 1812, declared against Britain over various grievances and fought to a draw, strengthened U.S. nationalism. A series of military incursions into Florida led Spain to cede it and other Gulf Coast territory in 1819.Expansion was aided by steam power, when steamboats began traveling along America’s large water systems, which were connected by new canals, such as the Erie and the I&M; then, even faster railroads began their stretch across the nation’s land.
From 1820 to 1850, Jacksonian democracy began a set of reforms which included wider white male suffrage; it led to the rise of the Second Party System of Democrats and Whigs as the dominant parties from 1828 to 1854. The Trail of Tears in the 1830s exemplified the Indian removal policy that resettled Indians into the west on Indian reservations. The U.S. annexed the Republic of Texas in 1845 during a period of expansionist Manifest destiny. The 1846 Oregon Treaty with Britain led to U.S. control of the present-day American Northwest. Victory in the Mexican–American War resulted in the 1848 Mexican Cession of California and much of the present-day American Southwest.
The California Gold Rush of 1848–49 spurred western migration and the creation of additional western states. After the American Civil War, new transcontinental railways made relocation easier for settlers, expanded internal trade and increased conflicts with Native Americans. Over a half-century, the loss of the American bison (sometimes called “buffalo”) was an existential blow to many Plains Indians cultures. In 1869, a new Peace Policy sought to protect Native-Americans from abuses, avoid further war, and secure their eventual U.S. citizenship, although conflicts, including several of the largest Indian Wars, continued throughout the West into the 1900s.
Differences of opinion and social order between northern and southern states in early United States society, particularly regarding Black slavery, ultimately led to the American Civil War. Initially, states entering the Union alternated between slave and free states, keeping a sectional balance in the Senate, while free states outstripped slave states in population and in the House of Representatives. But with additional western territory and more free-soil states, tensions between slave and free states mounted with arguments over federalism and disposition of the territories, whether and how to expand or restrict slavery.
With the 1860 election of Abraham Lincoln, the first president from the largely anti-slavery Republican Party, conventions in thirteen slave states ultimately declared secession and formed the Confederate States of America, while the federal government maintained that secession was illegal. The ensuing war was at first for Union, then after 1863 as casualties mounted and Lincoln delivered his Emancipation Proclamation, a second war aim became abolition of slavery. The war remains the deadliest military conflict in American history, resulting in the deaths of approximately 618,000 soldiers as well as many civilians.
Following the Union victory in 1865, three amendments were added to the U.S. Constitution: the Thirteenth Amendment prohibited slavery, the Fourteenth Amendment provided citizenship to the nearly four million African Americans who had been slaves, and the Fifteenth Amendment ensured that they had the right to vote. The war and its resolution led to a substantial increase in federal power aimed at reintegrating and rebuilding the Southern states while ensuring the rights of the newly freed slaves.
Southern white conservatives, calling themselves “Redeemers” took control after the end of Reconstruction. By the 1890–1910 period Jim Crow laws disenfranchised most blacks and some poor whites. Blacks faced racial segregation, especially in the South. Racial minorities occasionally experienced vigilante violence.
In the North, urbanization and an unprecedented influx of immigrants from Southern and Eastern Europe supplied a surplus of labor for the country’s industrialization and transformed its culture. National infrastructure including telegraph and transcontinental railroads spurred economic growth and greater settlement and development of the American Old West. The later invention of electric light and the telephone would also affect communication and urban life.
The end of the Indian Wars further expanded acreage under mechanical cultivation, increasing surpluses for international markets. Mainland expansion was completed by the purchase of Alaska from Russia in 1867. In 1893, pro-American elements in Hawaii overthrew the monarchy and formed the Republic of Hawaii, which the U.S. annexed in 1898. Puerto Rico, Guam, and the Philippines were ceded by Spain in the same year, following the Spanish–American War.
Rapid economic development during the late 19th and early 20th centuries fostered the rise of many prominent industrialists. Tycoons like Cornelius Vanderbilt, John D. Rockefeller, and Andrew Carnegie led the nation’s progress in railroad, petroleum, and steel industries. Banking became a major part of the economy, with J. P. Morgan playing a notable role. Edison and Tesla undertook the widespread distribution of electricity to industry, homes, and for street lighting. Henry Ford revolutionized the automotive industry. The American economy boomed, becoming the world’s largest, and the United States achieved great power status. These dramatic changes were accompanied by social unrest and the rise of populist, socialist, and anarchist movements. This period eventually ended with the advent of the Progressive Era, which saw significant reforms in many societal areas, including women’s suffrage, alcohol prohibition, regulation of consumer goods, greater antitrust measures to ensure competition and attention to worker conditions.
The United States remained neutral from the outbreak of World War I, in 1914, until 1917 when it joined the war as an “associated power”, alongside the formal Allies of World War I, helping to turn the tide against the Central Powers. In 1919, President Woodrow Wilson took a leading diplomatic role at the Paris Peace Conference and advocated strongly for the U.S. to join the League of Nations. However, the Senate refused to approve this, and did not ratify the Treaty of Versailles that established the League of Nations.
In 1920, the women’s rights movement won passage of a constitutional amendment granting women’s suffrage. The 1920s and 1930s saw the rise of radio for mass communication and the invention of early television. The prosperity of the Roaring Twenties ended with the Wall Street Crash of 1929 and the onset of the Great Depression. After his election as president in 1932, Franklin D. Roosevelt responded with the New Deal, which included the establishment of the Social Security system. The Great Migration of millions of African Americans out of the American South began before World War I and extended through the 1960s; whereas the Dust Bowl of the mid-1930s impoverished many farming communities and spurred a new wave of western migration.
At first effectively neutral during World War II while Germany conquered much of continental Europe, the United States began supplying material to the Allies in March 1941 through the Lend-Lease program. On December 7, 1941, the Empire of Japan launched a surprise attack on Pearl Harbor, prompting the United States to join the Allies against the Axis powers. During the war, the United States was referred as one of the “Four Policemen“ of Allies power who met to plan the postwar world, along with Britain, the Soviet Union and China. Though the nation lost more than 400,000 soldiers, it emerged relatively undamaged from the war with even greater economic and military influence.
The United States played a leading role in the Bretton Woods and Yalta conferences with the United Kingdom, the Soviet Union and other Allies, which signed agreements on new international financial institutions and Europe’s postwar reorganization. As an Allied victory was won in Europe, a 1945 international conference held in San Francisco produced the United Nations Charter, which became active after the war. The United States developed the first nuclear weapons and used them on Japan in the cities of Hiroshima and Nagasaki; causing the Japanese to surrender on September 2, ending World War II. Parades and celebrations followed in what is known as Victory Day, or V-J Day.
After World War II the United States and the Soviet Union jockeyed for power during what became known as the Cold War, driven by an ideological divide between capitalism and communism and, according to the school of geopolitics, a divide between the maritime Atlantic and the continental Eurasian camps. They dominated the military affairs of Europe, with the U.S. and its NATO allies on one side and the USSR and its Warsaw Pact allies on the other. The U.S. developed a policy of containment towards the expansion of communist influence. While the U.S. and Soviet Union engaged in proxy wars and developed powerful nuclear arsenals, the two countries avoided direct military conflict.
The United States often opposed Third World movements that it viewed as Soviet-sponsored. American troops fought communist Chinese and North Korean forces in the Korean War of 1950–53. The Soviet Union’s 1957 launch of the first artificial satellite and its 1961 launch of the first manned spaceflight initiated a “Space Race” in which the United States became the first nation to land a man on the moon in 1969. A proxy war in Southeast Asia eventually evolved into full American participation, as the Vietnam War.
At home, the U.S. experienced sustained economic expansion and a rapid growth of its population and middle class. Construction of an Interstate Highway System transformed the nation’s infrastructure over the following decades. Millions moved from farms and inner cities to large suburban housing developments. In 1959 Hawaii became the 50th and last U.S. state added to the country. The growing Civil Rights Movement used nonviolence to confront segregation and discrimination, with Martin Luther King Jr. becoming a prominent leader and figurehead. A combination of court decisions and legislation, culminating in the Civil Rights Act of 1968, sought to end racial discrimination. Meanwhile, a counterculture movement grew which was fueled by opposition to the Vietnam war, black nationalism, and the sexual revolution.
The launch of a “War on Poverty” expanded entitlements and welfare spending, including the creation of Medicare and Medicaid, two programs that provide health coverage to the elderly and poor, respectively, and the means-tested Food Stamp Program and Aid to Families with Dependent Children.
The 1970s and early 1980s saw the onset of stagflation. After his election in 1980, President Ronald Reagan responded to economic stagnation with free-market oriented reforms. Following the collapse of détente, he abandoned “containment” and initiated the more aggressive “rollback” strategy towards the USSR. After a surge in female labor participation over the previous decade, by 1985 the majority of women aged 16 and over were employed.
The late 1980s brought a “thaw” in relations with the USSR, and its collapse in 1991 finally ended the Cold War. This brought about unipolarity with the U.S. unchallenged as the world’s dominant superpower. The concept of Pax Americana, which had appeared in the post-World War II period, gained wide popularity as a term for the post-Cold War new world order.
After the Cold War, the conflict in the Middle East triggered a crisis in 1990, when Iraq under Sadaam Hussein invaded and attempted to annex Kuwait, an ally of the United States. Fearing that the instability would spread to other regions, President George H.W. Bush launched Operation Desert Shield, a defensive force buildup in Saudi Arabia, and Operation Desert Storm, in a staging titled the Gulf War; waged by coalition forces from 34 nations, led by the United States against Iraq ending in the successful expulsion of Iraqi forces from Kuwait, restoring the former monarchy.
Due to the dot-com boom, stable monetary policy under Alan Greenspan, and reduced social welfare spending, the 1990s saw the longest economic expansion in modern U.S. history, ending in 2001. Beginning in 1994, the U.S. entered into the North American Free Trade Agreement (NAFTA), linking 450 million people producing $17 trillion worth of goods and services. The goal of the agreement was to eliminate trade and investment barriers among the U.S., Canada, and Mexico by January 1, 2008. Trade among the three partners has soared since NAFTA went into force.
On September 11, 2001, Al-Qaeda terrorists struck the World Trade Center in New York City and the Pentagon near Washington, D.C., killing nearly 3,000 people. In response, the United States launched the War on Terror, which included war in Afghanistan and the 2003–11 Iraq War. In 2007, the Bush administration ordered a major troop surge in the Iraq War, which successfully reduced violence and led to greater stability in the region.
Government policy designed to promote affordable housing, widespread failures in corporate and regulatory governance, and historically low interest rates set by the Federal Reserve led to the mid-2000s housing bubble, which culminated with the 2008 financial crisis, the largest economic contraction in the nation’s history since the Great Depression. Barack Obama, the first African American and multiracial president, was elected in 2008 amid the crisis, and subsequently passed stimulus measures and the Dodd-Frank Wall Street Reform and Consumer Protection Act in an attempt to mitigate its negative effects. While the stimulus facilitated infrastructure improvementsand a relative decline in unemployment, Dodd-Frank has had a negative impact on business investment and small banks.
In 2010, the Obama administration passed the Affordable Care Act, which made the most sweeping reforms to the nation’s healthcare system in nearly five decades, including mandates, subsidies and insurance exchanges. The law caused a significant reduction in the number and percentage of people without health insurance, with 24 million covered during 2016, but remains controversial due to its impact on healthcare costs, insurance premiums, and economic performance. Although the recession reached its trough in June 2009, voters remained frustrated with the slow pace of the economic recovery. The Republicans, who stood in opposition to Obama’s policies, won control of the House of Representatives with a landslide in 2010 and control of the Senate in 2014.
American forces in Iraq were withdrawn in large numbers in 2009 and 2010, and the war in the region was declared formally over in December 2011. The withdrawal caused an escalation of sectarian insurgency, leading to the rise of the Islamic State of Iraq and the Levant, the successor of al-Qaeda in the region. In 2014, Obama announced a restoration of full diplomatic relations with Cuba for the first time since 1961. The next year, the United States as a member of the P5+1 countries signed the Joint Comprehensive Plan of Action, an agreement aimed to slow the development of Iran’s nuclear program.
Donald Trump, the wealthiest president in U.S. history and the first president with no political or military experience prior to taking office, was elected to office in the 2016 presidential election.
The land area of the contiguous United States is 2,959,064 square miles (7,663,940.6 km2). Alaska, separated from the contiguous United States by Canada, is the largest state at 663,268 square miles (1,717,856.2 km2). Hawaii, occupying an archipelago in the central Pacific, southwest of North America, is 10,931 square miles (28,311 km2) in area. The populated territories of Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and U.S. Virgin Islands together cover 9,185 square miles (23,789 km2).
The United States is the world’s third- or fourth-largest nation by total area (land and water), ranking behind Russia and Canada and just above or below China. The ranking varies depending on how two territories disputed by China and India are counted and how the total size of the United States is measured: calculations range from 3,676,486 square miles (9,522,055.0 km2) to 3,717,813 square miles (9,629,091.5 km2) to 3,796,742 square miles (9,833,516.6 km2) to 3,805,927 square miles (9,857,306 km2). Measured by only land area, the United States is third in size behind Russia and China, just ahead of Canada.
The coastal plain of the Atlantic seaboard gives way further inland to deciduous forests and the rolling hills of the Piedmont. The Appalachian Mountains divide the eastern seaboard from the Great Lakes and the grasslands of the Midwest. The Mississippi–Missouri River, the world’s fourth longest river system, runs mainly north–south through the heart of the country. The flat, fertile prairie of the Great Plains stretches to the west, interrupted by a highland region in the southeast.
The Rocky Mountains, at the western edge of the Great Plains, extend north to south across the country, reaching altitudes higher than 14,000 feet (4,300 m) in Colorado. Farther west are the rocky Great Basin and deserts such as the Chihuahua and Mojave. The Sierra Nevada and Cascade mountain ranges run close to the Pacific coast, both ranges reaching altitudes higher than 14,000 feet (4,300 m). The lowest and highest points in the contiguous United States are in the state of California, and only about 84 miles (135 km) apart. At an elevation of 20,310 feet (6,190.5 m), Alaska’s Denali (Mount McKinley) is the highest peak in the country and North America. Active volcanoes are common throughout Alaska’s Alexander and Aleutian Islands, and Hawaii consists of volcanic islands. The supervolcano underlying Yellowstone National Park in the Rockies is the continent’s largest volcanic feature.
The United States, with its large size and geographic variety, includes most climate types. To the east of the 100th meridian, the climate ranges from humid continental in the north to humid subtropical in the south. The Great Plains west of the 100th meridian are semi-arid. Much of the Western mountains have an alpine climate. The climate is arid in the Great Basin, desert in the Southwest, Mediterranean in coastal California, and oceanic in coastal Oregon and Washington and southern Alaska. Most of Alaska is subarctic or polar. Hawaii and the southern tip of Florida are tropical, as are the populated territories in the Caribbean and the Pacific. Extreme weather is not uncommon—the states bordering the Gulf of Mexico are prone to hurricanes, and most of the world’s tornadoes occur within the country, mainly in Tornado Alley areas in the Midwest and South.
The U.S. ecology is megadiverse: about 17,000 species of vascular plants occur in the contiguous United States and Alaska, and over 1,800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to 428 mammal species, 784 bird species, 311 reptile species, and 295 amphibian species. About 91,000 insect species have been described. The bald eagle is both the national bird and national animal of the United States, and is an enduring symbol of the country itself.
There are 58 national parks and hundreds of other federally managed parks, forests, and wilderness areas.Altogether, the government owns about 28% of the country’s land area. Most of this is protected, though some is leased for oil and gas drilling, mining, logging, or cattle ranching; about .86% is used for military purposes.
Environmental issues have been on the national agenda since 1970. Environmental controversies include debates on oil and nuclear energy, dealing with air and water pollution, the economic costs of protecting wildlife, logging and deforestation, and international responses to global warming. Many federal and state agencies are involved. The most prominent is the Environmental Protection Agency (EPA), created by presidential order in 1970. The idea of wilderness has shaped the management of public lands since 1964, with the Wilderness Act. The Endangered Species Act of 1973 is intended to protect threatened and endangered species and their habitats, which are monitored by the United States Fish and Wildlife Service.
|1610-1780 population data.
Note that the census numbers do
not include Native Americans until 1860.
|Race/Ethnicity (2015 ACS estimates)|
|American Indian and Alaska Native||0.8%|
|Native Hawaiian and Pacific Islander||0.2%|
|Some other race||4.8%|
|Hispanic/Latino (of any race)||17.6%|
|Non-Hispanic/Latino (of any race)||82.4%|
The U.S. Census Bureau estimated the country’s population to be 323,425,550 as of April 25, 2016, and to be adding 1 person (net gain) every 13 seconds, or about 6,646 people per day. The U.S. population almost quadrupled during the 20th century, from about 76 million in 1900. The third most populous nation in the world, after China and India, the United States is the only major industrialized nation in which large population increases are projected. In the 1800s the average woman had 7.04 children, by the 1900s this number had decreased to 3.56. Since the early 1970s the birth rate has been below the replacement rate of 2.1 with 1.86 children per woman in 2014. Foreign born immigration has caused the US population to continue its rapid increase with the foreign born population doubling from almost 20 million in 1990 to over 40 million in 2010, representing one third of the population increase. The foreign born population reached 45 million in 2015.[fn 8]
The United States has a birth rate of 13 per 1,000, which is 5 births below the world average. Its population growth rate is positive at 0.7%, higher than that of many developed nations. In fiscal year 2012, over one million immigrants (most of whom entered through family reunification) were granted legal residence. Mexico has been the leading source of new residents since the 1965 Immigration Act. China, India, and the Philippines have been in the top four sending countries every year since the 1990s. As of 2012, approximately 11.4 million residents are illegal immigrants. As of 2015, 47% of all immigrants are Hispanic, 26% are Asian, 18% are white and 8% are black. The percentage of immigrants who are Asian is increasing while the percentage who are Hispanic is decreasing.
According to a survey conducted by the Williams Institute, nine million Americans, or roughly 3.4% of the adult population identify themselves as homosexual, bisexual, or transgender. A 2016 Gallup poll also concluded that 4.1% of adult Americans identified as LGBT. The highest percentage came from the District of Columbia (10%), while the lowest state was North Dakota at 1.7%. In a 2013 survey, the Centers for Disease Control and Prevention found that 96.6% of Americans identify as straight, while 1.6% identify as gay or lesbian, and 0.7% identify as being bisexual.
In 2010, the U.S. population included an estimated 5.2 million people with some American Indian or Alaska Native ancestry (2.9 million exclusively of such ancestry) and 1.2 million with some native Hawaiian or Pacific island ancestry (0.5 million exclusively). The census counted more than 19 million people of “Some Other Race” who were “unable to identify with any” of its five official race categories in 2010, over 18.5 million (97%) of whom are of Hispanic ethnicity.
The population growth of Hispanic and Latino Americans (the terms are officially interchangeable) is a major demographic trend. The 50.5 million Americans of Hispanic descent are identified as sharing a distinct “ethnicity” by the Census Bureau; 64% of Hispanic Americans are of Mexican descent. Between 2000 and 2010, the country’s Hispanic population increased 43% while the non-Hispanic population rose just 4.9%. Much of this growth is from immigration; in 2007, 12.6% of the U.S. population was foreign-born, with 54% of that figure born in Latin America.[fn 9]
About 82% of Americans live in urban areas (including suburbs); about half of those reside in cities with populations over 50,000. The US has numerous clusters of cities known as megaregions, the largest being the Great Lakes Megalopolis followed by the Northeast Megalopolis and Southern California. In 2008, 273 incorporated municipalities had populations over 100,000, nine cities had more than one million residents, and four global cities had over two million (New York, Los Angeles, Chicago, and Houston). There are 52 metropolitan areas with populations greater than one million. Of the 50 fastest-growing metro areas, 47 are in the West or South. The metro areas of San Bernardino, Dallas, Houston, Atlanta, and Phoenix all grew by more than a million people between 2000 and 2008.
|Leading population centers (see complete list)|
|Rank||Core city (cities)||Metro area population||Metropolitan Statistical Area||Region||
New York City
|1||New York||20,182,305||New York–Newark–Jersey City, NY–NJ–PA MSA||Northeast|
|2||Los Angeles||13,340,068||Los Angeles–Long Beach–Anaheim, CA MSA||West|
|3||Chicago||9,551,031||Chicago–Joliet–Naperville, IL–IN–WI MSA||Midwest|
|4||Dallas–Fort Worth||7,102,796||Dallas–Fort Worth–Arlington, TX MSA||South|
|5||Houston||6,656,947||Houston–The Woodlands-Sugar Land MSA||South|
|6||Washington, D.C.||6,097,684||Washington, DC–VA–MD–WV MSA||South|
|7||Philadelphia||6,069,875||Philadelphia–Camden–Wilmington, PA–NJ–DE–MD MSA||Northeast|
|8||Miami||6,012,331||Miami–Fort Lauderdale–Pompano Beach, FL MSA||South|
|9||Atlanta||5,710,795||Atlanta–Sandy Springs–Roswell, GA MSA||South|
|10||Boston||4,774,321||Boston–Cambridge–Quincy, MA–NH MSA||Northeast|
|11||San Francisco||4,656,132||San Francisco–Oakland–Fremont, CA MSA||West|
|12||Phoenix||4,574,531||Phoenix–Mesa–Glendale, AZ MSA||West|
|13||Riverside–San Bernardino||4,489,159||Riverside–San Bernardino–Ontario, CA MSA||West|
|14||Detroit||4,302,043||Detroit–Warren–Livonia, MI MSA||Midwest|
|15||Seattle||3,733,580||Seattle–Tacoma–Bellevue, WA MSA||West|
|16||Minneapolis–St. Paul||3,524,583||Minneapolis–St. Paul–Bloomington, MN–WI MSA||Midwest|
|17||San Diego||3,299,521||San Diego–Carlsbad–San Marcos, CA MSA||West|
|18||Tampa–St. Petersburg||2,975,225||Tampa–St. Petersburg–Clearwater, FL MSA||South|
|19||Denver||2,814,330||Denver–Aurora–Lakewood, CO MSA||West|
|20||St. Louis||2,811,588||St. Louis MO–IL MSA||Midwest|
|Based on 2015 population estimates from the U.S. Census Bureau|