United States of America

The United States of America is a vast federal presidential republic located in North America. Known for its immense geographic diversity, economic power, and cultural influence, it stands as one of the most influential nations in the modern world. From its origins with indigenous peoples to its current status as a global leader in technology and finance, the U.S. is defined by a complex history of expansion, conflict, and innovation.

Key Facts

ภาพประกอบบทความ — ภาพประกอบจากบทความต้นฉบับ

Capital: Washington, D.C.
Largest City: New York City
Population: Approximately 341.8 million (2025 estimate)
Total Area: 3,796,742 sq mi (3rd largest in the world)
Currency: U.S. dollar ($)
Government: Federal presidential republic
Nominal GDP: $32.384 trillion (1st globally, 2026 estimate)

Historical Evolution

States and territories by partisan control, as of February 2025: Divided partisan control

Long before European arrival, the land was inhabited by diverse indigenous peoples. Settlements such as Cliff Palace, built between 1200 and 1275 by ancestors of the Native American Pueblo peoples, demonstrate the sophisticated societies that existed early on.

Cliff Palace, a settlement of ancestors of the Native American Pueblo peoples in present-day Montezuma County, Colorado, built between c. 1200 and 1275[36]

European exploration and colonization began in earnest between 1513 and 1765, with Britain, France, and Spain competing for territorial control across the continent.

The colonial possessions of Britain (the Thirteen Colonies in pink and others in purple), France (in blue), and Spain (in orange) in North America, 1750

The American Revolution led to the Declaration of Independence on July 4, 1776, marking the break from Great Britain. This was followed by the establishment of the Confederation in 1781 and the ratification of the Constitution on March 4, 1789.

See caption. — The Declaration of Independence portrait depicts the Committee of Five presenting the Declaration to the Continental Congress on June 28, 1776, in Philadelphia.

The 19th century was characterized by rapid westward expansion and the internal strife of the Civil War (1861–1865), which centered on issues of slavery and state rights. Following the war, the nation entered the Reconstruction, Gilded Age, and Progressive Era, eventually emerging as a global power through its involvement in World War I and World War II.

Historical territorial expansion of the United States — Territorial expansion of the United States

The mid-20th century saw the dawn of the nuclear age with the 1945 Trinity test and the subsequent Cold War. This era also sparked a social revolution, highlighted by the Civil Rights Movement and the 1963 March on Washington.

The 1945 American Trinity test, the first-ever detonation of a nuclear weapon

Civil rights activists during the March on Washington for Jobs and Freedom in Washington, D.C. in August 1963

Contemporary history has been shaped by the end of the Cold War in 1991 and significant events such as the September 11 attacks in 2001.

The Twin Towers in New York City during the September 11 attacks of 2001

Geography and Climate

The United Nations headquarters has been situated along the East River in Midtown Manhattan since 1952; in 1945, the United States was a founding member of the UN.

The United States possesses a highly varied topography, ranging from the coastal plains of the Atlantic and Pacific to the rugged peaks of the Rocky Mountains and the depths of the Grand Canyon in Arizona.

The climate is equally diverse, categorized by various Köppen climate types, which influence the nation's biodiversity and agricultural output.

The Köppen climate types of the United States

The bald eagle, the national emblem since 1782, was officially declared the national bird in 2024.

A bald eagle — The bald eagle has been the national emblem of the United States since 1782, and was officially declared the national bird in 2024.[216]

Government and Political Structure

The Mexico–United States border wall between San Diego (left) and Tijuana (right)

The U.S. operates as a federal presidential republic. The government is divided into three branches: the Legislature (Congress, consisting of the Senate and the House of Representatives), the Executive (led by the President), and the Judiciary (headed by the Supreme Court).

The nation's administrative reach extends beyond the 50 states to include territories such as Puerto Rico, Guam, and American Samoa.

Territories of the United States include American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands.

Additionally, there are 326 Indian reservations across the country, reflecting the ongoing relationship with Native American tribes.

Map of the 326 Indian reservations in the United States; 231 recognized Alaska Native tribes are not shown.

The U.S. maintains a massive defense and security apparatus, with the Pentagon serving as the headquarters for the Department of Defense and the J. Edgar Hoover Building housing the FBI.

J. Edgar Hoover Building, the headquarters of the Federal Bureau of Investigation (FBI), in Washington, D.C.

Economy and Infrastructure

The Statue of Liberty, a large teal bronze sculpture on a stone pedestal — The Statue of Liberty (Liberty Enlightening the World) on Liberty Island in New York Harbor was an 1886 gift from France that has become an iconic symbol of the American Dream.[495]

The United States holds the world's largest nominal GDP. The U.S. dollar serves as the primary reserve currency globally, and New York City stands as the world's principal financial center, home to the New York Stock Exchange.

Obverse of a US$1 bill — The U.S. dollar is the most-used currency in international transactions and the world's foremost reserve currency.

New York City is the world's principal financial center, and its metropolitan area is the world's largest metropolitan economy.

The New York Stock Exchange on Wall Street, the world's largest stock exchange by market capitalization[336]

Innovation is driven by hubs like Silicon Valley in California, the foremost technology center in the world. The nation also leads in space exploration, being the only country to have landed humans on the Moon during the 1969 Apollo 11 mission.

California's Silicon Valley is the largest and foremost technology and innovation hub in the world.[371][372]

Astronauts Buzz Aldrin and Neil Armstrong (seen in visor reflection) during the 1969 Apollo 11 mission, the first crewed Moon landing. The United States is the only country to have landed humans on the Moon.

Infrastructure is characterized by an extensive interstate highway system and high-traffic hubs like Hartsfield–Jackson Atlanta International Airport, the world's busiest airport by passenger traffic.

Interchange between Interstate 10 and Interstate 45 in Houston, Texas

Hartsfield–Jackson Atlanta International Airport, serving the Atlanta metropolitan area, is the world's busiest airport by passenger traffic with over 75 million passengers as of 2021.[417][418]

Demographics and Society

Comcast Center in Philadelphia, headquarters of Comcast, one of the world's largest telecommunications companies and media conglomerates

The American population is a multicultural blend. As of 2020, the racial composition is approximately 61.6% White, 12.4% Black, 6% Asian, and 1.1% Native American, with a significant portion identifying as two or more races.

While English is the primary language, the U.S. is linguistically diverse due to high levels of immigration.

Religion remains a significant part of society, with Christianity (including Protestantism and Catholicism) being the most prevalent faith, though a growing percentage of the population is unaffiliated.

The population is largely urbanized, with many residents living in suburbs and exurbs.

Houses near farmland — Most Americans live in suburbs and exurbs, such as Monroe Township, New Jersey, in the New York metropolitan area.

Education and Health

The U.S. is home to world-leading universities, with 77% of college students attending public institutions. In healthcare, the Texas Medical Center in Houston is the largest medical complex globally.

The Texas Medical Center in Houston is the largest medical complex in the world.[468][469] In 2018, it employed 120,000 people and treated 10 million patients.[470]

Photograph of the University of Virginia — Some 77% of American college students attend public institutions[480] such as the University of Virginia, founded by Thomas Jefferson in 1819.

Culture and Arts

Haute couture fashion models on the catwalk during New York Fashion Week

American culture is a global export, from the cinema of Hollywood to the music of Nashville and the theaters of Broadway.

Broadway theaters in Theater District, Manhattan

The Country Music Hall of Fame and Museum in Nashville, Tennessee

The Hollywood Sign in the Hollywood Hills, often regarded as the symbol of the American film industry

Literature has been shaped by figures like Mark Twain, while visual arts include iconic works such as Grant Wood's American Gothic.

Photograph of Mark Twain — Mark Twain, whom William Faulkner called "the father of American literature"[534]

American Gothic (1930) by Grant Wood is one of the most famous American paintings and is widely parodied.[580]

Daily life is marked by unique traditions, such as the Thanksgiving dinner, and a passion for sports, with American football being the most popular.

A Thanksgiving dinner with roast turkey, mashed potatoes, pickles, corn, candied yams, cranberry jelly, shrimps, stuffing, green peas, deviled eggs, green salad, and apple sauce

American football is the most popular sport in the United States; in this 2009 National Football League game, Carolina Panthers quarterback Jake Delhomme (number 17) throws a forward pass against the Dallas Cowboys.

Category	Detail
Official Motto	In God We Trust
National Anthem	The Star-Spangled Banner
Population (2025 Est.)	341,784,857
GDP (Nominal 2026 Est.)	$32.384 Trillion
HDI (2023)	0.938 (Very High)

Frequently Asked Questions

What is the official language of the United States?

While English is the most widely spoken language and the primary language of government, the United States does not have an official language at the federal level.

How is the U.S. government structured?

The U.S. is a federal presidential republic with a separation of powers between the legislative (Congress), executive (President), and judicial (Supreme Court) branches.

Which state has the largest population?

California is the most populous state, with approximately 39.4 million residents.

What is the significance of the U.S. dollar?

The U.S. dollar is the world's foremost reserve currency and the most-used currency in international transactions.

When did the United States declare independence?

The United States declared its independence from Great Britain on July 4, 1776.