United States of America

At a glance

What is the United States?

A federation of fifty states with a written constitution, a directly elected president and a bicameral Congress, occupying the middle of North America from the Atlantic to the Pacific, plus Alaska and Hawaii. The continental territory was acquired in stages — thirteen colonies, the Louisiana Purchase, the Mexican cession, Texas, Oregon, Alaska — and the political system was designed for a small agrarian republic and then stretched to govern a continental empire.

That is the central tension of its history: the Constitution of 1787 was written for a country of four million people on the eastern seaboard, and it has governed a country of three hundred and forty million people across a continent and an ocean without being replaced. Whether that is a triumph of design or an accident of history is the argument every generation has.

How did it begin?

With a declaration and a failed constitution. The Second Continental Congress declared independence on 4 July 1776, fought and won a war with British help, and then governed through the Articles of Confederation — a league of states with no power to tax, no executive and no court. It failed within a decade.

The Constitutional Convention met in Philadelphia in 1787. Seventy-four delegates were appointed, fifty-five attended, and thirty-nine signed. They created a federal government with enumerated powers, a bicameral legislature (the compromise between large and small states), an electoral college, and a bill of rights added in 1791. The document's compromises with slavery — the three-fifths clause, the slave-trade clause, the fugitive clause — were the price of union, and they set up the war that came seventy years later.

How does the federal system work?

Through three branches and a division of sovereignty. Congress has two chambers — the House of Representatives, apportioned by population (435 members), and the Senate, two per state (100) — and writes federal law. The president is elected indirectly by the electoral college and commands the executive and the armed forces. The Supreme Court, nine justices appointed for life, can strike down legislation as unconstitutional — a power it gave itself in Marbury v. Madison in 1803 and has used ever since.

The states keep whatever powers the Constitution does not grant to Washington: criminal law, education, most health policy, land use, and the running of elections. That division is why American government looks weak and intrusive at the same time: the federal government cannot simply order a state to do something, and the states can refuse. It is also why the country's politics are so local — school boards, prosecutors and state legislatures matter enormously.

The system was designed to be slow. Separation of powers, federalism, a bicameral legislature and judicial review all make it hard to change anything quickly, which was the point: the founders feared concentrated power more than they feared paralysis.

How did it grow?

By purchase, conquest and removal. The Louisiana Purchase of 1803 doubled the country for $15 million — about four cents an acre — and opened the Mississippi. Florida was acquired from Spain in 1819, Texas annexed in 1845, Oregon divided with Britain in 1846, and the Mexican War added about 525,000 square miles for $15 million in 1848, including California and the gold.

The expansion was not empty land. The Indian Removal Act of 1830 forced about 100,000 Native people from the south-east to Indian Territory west of the Mississippi between 1830 and 1850, and the Cherokee removal — the Trail of Tears — killed thousands. The northern tribes were dispossessed by treaty and war across the nineteenth century, and the reservation system was built on the lands the United States did not want. The frontier was not a place where civilisation met wilderness; it was a place where one polity took land from others and called the result progress.

Why did it split?

Because slavery was a national institution and the political system could not contain it. In 1790 the United States held 3,929,214 people, of whom 697,897 were enslaved. By 1860 it held 31.4 million, of whom 3.95 million were enslaved. The northern states had abolished slavery; the southern economy depended on it; and every territorial acquisition reopened the question of whether new states would be free or slave.

The war began in April 1861 after eleven states seceded, and ended in April 1865. The Union enlisted 2,672,341 men. The traditional death toll is about 620,000; J. David Hacker's revision puts it at about 750,000, and the higher figure is now widely used, though it should be attributed rather than stated flatly. The war freed four million people — the Emancipation Proclamation of 1863 in the rebel states, the Thirteenth Amendment everywhere in 1865 — and destroyed the southern economy.

What came after the war?

Reconstruction: twelve years of federal intervention in the defeated South, with the Fourteenth Amendment (1868) guaranteeing citizenship and equal protection, the Fifteenth (1870) protecting the vote, and federal troops enforcing both. It ended in 1877, when the last troops withdrew as part of a political bargain, and the South then built Jim Crow — segregation, disfranchisement and terror — which lasted until the 1960s.

Reconstruction is the hinge of American history. It decided that the war would end slavery but not racial hierarchy, and the consequences — segregation, the civil rights movement, the racial wealth gap — run through everything after.

How did it become an industrial power?

By rails, steel, immigration and cities. Railway mileage rose from 35,085 miles in 1865 to 254,037 in 1916; steel production from 1.25 million tons in 1865 to 80 million tons in 1945; electricity output from 5.86 billion kWh in 1902 to 271 billion in 1945. The 1890 census counted 62.98 million people, and its report on the frontier — the famous line about the closing of a continuous line of settlement — became a founding text of American self-understanding, though Turner's 1893 essay quotes it slightly differently.

Immigration supplied the labour: 23.9 million people arrived between 1880 and 1920, and the foreign-born population rose from 6.68 million to 13.92 million. The urban share of the population went from 28.2 per cent in 1880 to 51.2 per cent in 1920 — the year the census announced that America was majority urban.

Who came to America?

Successive waves, each despised by the last. The first great wave, 1840–60, was Irish and German, Catholic and poor, and it produced the Know-Nothing party and the first nativist politics. The second, 1880–1920, was southern and eastern European — Italian, Polish, Russian, Jewish — 23.9 million people, and it built the industrial cities. The third, after 1965, was Asian and Latin American, and it changed the country's demography again.

Internal migration mattered as much. The Great Migration of African Americans out of the rural South, roughly 1915–70, moved millions of people to northern and western cities and created the urban black America whose politics produced the civil rights movement. Suburbanisation after 1945 moved the white middle class out of the cities, and the federal highway programme, the mortgage guarantee and the GI Bill made the suburbs the centre of American life — and of American segregation.

The result is a country that is simultaneously the most immigrant-shaped society in the developed world and one of the most segregated by race and income. Both facts are true, and the argument about which one defines the country is the culture war.

What happened to Native Americans after 1900?

The United States kept taking their land and then tried to make them disappear as nations. The Dawes Act of 1887 had broken communal reservation land into individual allotments and sold the "surplus" to settlers, cutting the Native land base by roughly two-thirds. The Indian Citizenship Act of 1924 made Native people citizens without consulting them, and the termination policy of the 1953–60s tried to abolish tribes altogether and relocate people to cities.

The reversal came in the 1960s and 1970s: the 1934 Indian Reorganization Act had already restored some tribal government, and the self-determination policy of the 1970s recognised tribal sovereignty, gave tribes control of federal programmes and, in the courts, confirmed treaty rights to land, water and fish. The 1975 Indian Self-Determination and Education Assistance Act is the legal hinge. Today there are 574 federally recognised tribes, and tribal gaming, resource rights and jurisdiction are substantial economic and political facts.

The story is not one of disappearance but of survival under pressure. Native nations remain sovereign entities within the United States — a constitutional oddity that the Supreme Court has repeatedly had to explain, and that no other settler colony has quite replicated.

When did it become an empire?

In 1898, in a war with Spain that lasted four months and ended with the United States holding Cuba (briefly), Puerto Rico, Guam and the Philippines. The Philippines were the largest acquisition and the most contested: the United States annexed them, fought a war against Filipino nationalists that killed 4,200 American soldiers and perhaps 20,000 Filipino combatants, and, in the State Department's own phrasing, "as many as 200,000" civilians. The Supreme Court's Insular Cases held that the Constitution did not fully follow the flag, and the United States governed its new possessions as colonies while calling itself a republic.

Hawaii was annexed in 1898; Alaska had been bought from Russia in 1867. Both became states in 1959 — Alaska on 7 July 1958 by statute, Hawaii on 18 March 1959 — and those are the last territorial additions to the union.

What did the world wars do?

The First World War made the United States a creditor and a power. It entered in April 1917, mobilised 4,734,991 men and lost 116,516 dead; the 1918 influenza pandemic killed more Americans than the war. The Senate rejected the Treaty of Versailles and the League of Nations, and the country retreated into the 1920s.

The Second World War made it a superpower. After Pearl Harbor — 2,403 dead — the United States mobilised 16,112,566 people, lost 405,399 dead, and produced the industrial output that armed the Allies. It ended the war with two atomic bombs: about 80,000 dead at Hiroshima and about 40,000 at Nagasaki, with the usual range for Hiroshima running from 70,000 to 90,000. In 1945 the United States had the only intact industrial economy among the great powers and the only atomic bomb.

What is the economy today?

The largest in the world, and post-industrial. Agriculture employs about 1 per cent of the workforce; manufacturing about 8 per cent; the rest is services — finance, health care, technology, retail, education. The country's comparative advantage is no longer steel but software, capital and the dollar, which remains the world's reserve currency.

The economy's defining features are scale and inequality. American GDP per head is among the highest in the world, and so is its inequality among rich countries: the top tenth take a far larger share of income than in western Europe, and the racial wealth gap is enormous. Health care is the most expensive in the world per head and does not produce the best outcomes. Productivity growth has slowed since the 1970s, and the national debt is large and rising.

Politically, the economy is a battle between two stories: that the market produces growth and the state should get out of the way, and that the market produces inequality and the state should correct it. The New Deal, the Great Society, the Reagan revolution and the Affordable Care Act are chapters of that argument, and it is not settled.

What was the New Deal?

The response to the Depression. Unemployment peaked at 25.59 per cent in May 1933 — the monthly figure, not the 24.9 per cent annual average, and mixing the two is a common error. The New Deal created the Securities and Exchange Commission, the Federal Deposit Insurance Corporation, the Tennessee Valley Authority and Social Security (1935), regulated wages and hours, and put millions of people to work. It did not end the Depression; the war did. But it created the institutional framework of American social policy for the next eighty years.

What was the Depression like?

A collapse of everything at once. Between 1929 and 1933 industrial production fell by about half, prices fell by a third, and a quarter of the workforce lost its job. Banks failed in thousands, farms were foreclosed, and in the southern plains the dust storms of the 1930s blew the topsoil away and drove families west along Route 66 to California — the migration that produced The Grapes of Wrath and the Okie stereotype.

The federal response changed the country's political economy. The New Deal regulated banks and securities, guaranteed deposits, built dams and power stations, employed millions in the Civilian Conservation Corps and the Works Progress Administration, and created Social Security. It also created a coalition — labour, the South, immigrants, African Americans — that dominated American politics for a generation, until the civil rights movement split the Democrats and the Republicans took the South.

How did it fight the Cold War?

By containment, alliance and spending. NATO was founded in 1949; defence spending rose from 5 per cent of GDP in 1950 to 14.2 per cent in 1953, and settled at about 3.4 per cent by 2024. The United States fought in Korea (1950–53, 36,574 dead in theatre) and Vietnam (1964–73, 58,220 dead), maintained a nuclear arsenal, and backed anti-communist governments across the world — including, in Iran, Guatemala, Chile and elsewhere, governments that were not democratic.

The Cold War ended in 1991 with the collapse of the Soviet Union, and the United States became the only superpower. Its defence spending in 2024 was $997 billion, 37 per cent of the world total; its share of world GDP had fallen from 39.6 per cent in 1960 to 26.2 per cent, but it remained the largest economy.

What was the Cold War like at home?

Frightening and profitable. The early Cold War brought the House Un-American Activities Committee, the Smith Act trials, the Rosenberg executions and McCarthyism — a politics of accusation that damaged careers and chilled dissent. The arms race and the space race produced the military-industrial complex that Eisenhower warned against in his farewell address, and the interstate highway system, built as much for evacuation as for commerce.

The Vietnam War split the country. By 1968, with 16,899 American dead that year alone, the anti-war movement had become a mass phenomenon, the Democratic Party had fractured, and the credibility of the government had collapsed. The war ended in 1973, the draft ended the same year, and the country has fought its subsequent wars with volunteers — a change with profound consequences for who serves and who bears the cost.

How did the South change?

Twice, in opposite directions. After the Civil War it was poor, rural, segregated and politically solid Democratic — the "Solid South" that blocked civil rights legislation for decades. After 1945 the federal government and the Cold War changed it: military bases, defence plants and air conditioning moved industry and people south, and the "Sun Belt" grew while the Rust Belt declined.

The civil rights movement then broke the Solid South and created the modern party alignment: the South became Republican, and the national parties sorted by race and region. That realignment is the single most important fact in American politics since 1965, and it explains why the country's political geography looks the way it does today.

What was Jim Crow?

The system of racial segregation and disfranchisement that replaced slavery in the South between the 1890s and the 1960s. It was codified in state constitutions and statutes — poll taxes, literacy tests, white primaries, grandfather clauses — and enforced by custom and violence. "Separate but equal" was the legal formula, endorsed by the Supreme Court in Plessy v. Ferguson in 1896 and dismantled only in Brown in 1954.

It was not confined to the South. Northern cities segregated housing through covenants and redlining, schools through district boundaries, and labour markets through discrimination; the federal government itself segregated its workforce and its armed forces until the 1940s and 1950s. The civil rights movement of 1954–65 attacked the southern legal system, and the Fair Housing Act of 1968 attacked the northern one, but the economic consequences — the racial wealth gap, segregated schools, mass incarceration — outlasted the law.

What changed at home?

The civil rights movement. Brown v. Board of Education (1954) ended school segregation in law; the Montgomery bus boycott (1955–56) made Martin Luther King a national figure; the Civil Rights Act of 1964 banned segregation in public accommodation and employment; the Voting Rights Act of 1965 enforced the Fifteenth Amendment. The movement did not end inequality, but it ended the legal architecture of Jim Crow, and it is the domestic achievement on which the country's self-image now rests.

Why does the map break in 1945?

It does not, and that is worth saying plainly. The border data is continuous for the United States from 1776 to 2024; 1967 is only a row boundary where the geometry was redrawn and coarsened — the area changes from 10.15 to 9.61 million km² and the vertex count from 2,376 to 1,884. No territory changed hands in 1967; the last additions were Alaska and Hawaii in 1959.

The apparent gap is a fault in this site's build, not in history: for 1945–49 the American landmass is filed in the source data under a mislabelled entity ("american-occupation-zone", with a bounding box covering the United States, Alaska, Hawaii and the Pacific), and for 1950–66 it is absent altogether. The map restores the United States in 1967. That is a data defect, and it is flagged here rather than presented as a historical event.

Where is it now?

The post-Cold War decades: the Gulf War of 1991 (383 American dead, 148 in battle), the attacks of 11 September 2001 (2,973 dead), the wars in Afghanistan and Iraq (6,855 American dead by July 2015, and Afghanistan alone 2,461 by August 2021), the financial crisis of 2008, the Obama, Trump and Biden presidencies, the 2020 election (306 electoral votes to 232, and a 81.3 million to 74.2 million popular vote) and the attack on the Capitol on 6 January 2021, and the 2024 election (312 to 226).

The country is 340 million people, the third largest in the world, with the largest economy and the largest military budget. It is also more politically divided than at any time since the 1860s, and the question of whether its institutions can hold that division is the live one.

What is the argument about it?

Three arguments, all live. The first is about exceptionalism — the claim that the United States is uniquely free, uniquely opportunity-giving, or uniquely hypocritical. The evidence for the first is its constitution, its immigration and its economic dynamism; the evidence against is slavery, Jim Crow, Native dispossession and mass incarceration. Most historians now treat exceptionalism as a claim to be explained rather than a fact to be celebrated.

The second is about empire. The United States does not call itself an empire, but it has governed dependencies, maintained hundreds of military bases, overthrown governments and fought wars on four continents. The question is whether that is an empire in the Roman or British sense or a different kind of power that the older vocabulary cannot describe.

The third is about whether the institutions can hold. The 2020 election, the attack on the Capitol, the collapse of trust in institutions and the polarisation of the parties have made the durability of the constitutional system a live question rather than a complacent one. The country has survived a civil war, a depression and a cold war; whether it survives its present division is the open question of the century.

What is the place of religion?

Unusually large for a rich country. Church attendance and belief in God are far higher than in western Europe, and religion has been a political force since the Great Awakenings: abolitionism, temperance, the Social Gospel, the civil rights movement (whose rhetoric was biblical), and the Christian right that emerged in the 1970s and became a pillar of the Republican coalition.

The Constitution's First Amendment forbids an establishment of religion and guarantees its free exercise, and the courts have spent two centuries drawing the line between the two — school prayer, public display, funding, and the balance between religious liberty and anti-discrimination law. Religion is also the main carrier of American voluntary association: congregations, charities and schools that do much of what the state does elsewhere.

Common myths about the United States

Timeline of the United States

What the map shows next

At 1790 on the map the United States is thirteen states on the seaboard, New France is gone, and the Haudenosaunee still hold the interior.

At 1870 on the map the country spans the continent, the Dominion of Canada has just been created to its north, and Reconstruction is under way.

At 1940 on the map the United States is emerging as the world's industrial arsenal, and the Greenland crisis has made the Arctic strategic.