What was the American Revolutionary War? Causes and outcome

The American Revolutionary War, also called the American War of Independence, was the war fought from 1775 to 1783 between Great Britain and thirteen of its North American colonies, which declared themselves the independent United States in 1776. It began at Lexington and Concord in Massachusetts, turned on the American victory at Saratoga and the alliance with France that followed, and was effectively decided at Yorktown in 1781. Britain recognized American independence in the Treaty of Paris in 1783.

In short

• The war grew out of a twelve-year quarrel over whether Parliament in London could tax colonists who elected no one to it.
• Britain was far richer and stronger, but it was fighting 5,000 kilometers from home in a vast, mostly rural country, and from 1778 against France and later Spain as well.
• The war won independence; the wider American Revolution, in ideas and government, began before it and went on after it.

Why did the colonies break with Britain?

The quarrel started with money. Britain came out of the Seven Years' War in 1763, the French and Indian War in America, with a huge debt and a larger empire to defend. Parliament decided the colonies should help pay. As the State Department's historians put it, a series of trade and tax laws passed between 1763 and 1775 created the tensions that led to the Revolution. The Sugar Act of 1764, the Stamp Act of 1765, which taxed printed paper from newspapers to legal documents, and the Townshend duties of 1767 on goods such as glass, paper and tea were each met with boycotts, protests and riots.

The colonists' objection was a principle as much as the cost. They accepted that Parliament could regulate the empire's trade, but held that only their own elected assemblies could tax them, and they had no members in Parliament: "no taxation without representation." Parliament held that it had full authority over the colonies whether they were represented or not. Each crisis made the gap wider.

The timeline of the slide toward war, and the war itself:

Date	What happened
1765	Stamp Act; protests across the colonies force its repeal the next year
5 March 1770	British soldiers kill five people in the Boston Massacre
16 December 1773	Boston Tea Party: colonists dump 342 chests of tea into the harbor
1774	Parliament's Coercive Acts punish Massachusetts; the First Continental Congress meets
19 April 1775	Fighting at Lexington and Concord; the war begins
17 June 1775	Battle of Bunker Hill near Boston; Congress has just named George Washington commander
4 July 1776	Congress adopts the Declaration of Independence
August–September 1776	British forces win the Battle of Long Island and take New York City, their base for the rest of the war
26 December 1776	Washington crosses the Delaware and surprises the Hessian garrison at Trenton
17 October 1777	British general John Burgoyne surrenders his army at Saratoga, New York
Winter 1777–1778	The Continental Army endures Valley Forge and is retrained
6 February 1778	France signs a treaty of alliance with the United States
1778–1781	Britain shifts the war south, taking Savannah and Charleston
19 October 1781	Cornwallis surrenders at Yorktown, Virginia, trapped by American and French armies and a French fleet
3 September 1783	Treaty of Paris; Britain recognizes the United States

How did the colonists win?

Washington's army lost more battles than it won. It survived, and survival was enough, because Britain had to conquer and hold a continent while the Americans only had to avoid being destroyed.

	Great Britain	The United States
People	About 8 million in Britain in 1775	About 2.5 million in the colonies, of whom about half a million were enslaved
Strengths	The world's strongest navy, a professional army, money and credit, nearly 30,000 hired German soldiers, loyalist and most Native allies	Fighting at home; a population that was 90% rural and beyond the reach of British garrisons; Washington's persistence; French money, troops and ships from 1778
Weaknesses	Orders and supplies took weeks to cross the Atlantic; no single capital to capture; from 1778 a global war with France, then Spain and the Netherlands	Almost no navy; a weak Congress that could not tax; a paper currency that collapsed; short enlistments; a divided population

Those figures come from the American Battlefield Trust. The key was France. After Saratoga showed that the Americans could beat a British army, France, eager to avenge its losses in 1763, signed the Treaty of Alliance on 6 February 1778. It had already been sending arms in secret. Spain joined the war against Britain in 1779 and the Netherlands in 1780, and Britain had to defend the Caribbean, Gibraltar and India as well as fight in America.

Yorktown showed what the alliance meant. In 1781 the British general Charles Cornwallis took his army to the Virginia coast to be supplied by sea. A French fleet under the Comte de Grasse beat off the Royal Navy at the mouth of the Chesapeake Bay in September, while Washington and the French general Rochambeau marched their armies south and laid siege. Cornwallis surrendered more than 8,000 men on 19 October. Britain still held New York, but Parliament lost the will to go on, and peace talks began.

Who else fought, and what did they win or lose?

The war was also a civil war. Many colonists, known as loyalists, stayed faithful to the Crown, and about 25,000 of them fought for Britain. After the war, tens of thousands of loyalists left for Canada, Britain and the Caribbean, some of them taking enslaved people with them.

For enslaved Black Americans, the war offered a chance at freedom from whichever side would grant it. British commanders, starting with the governor of Virginia in 1775, promised freedom to enslaved people who escaped from rebel owners and joined them, and about 20,000 Black Americans served with the British. About 7,000 served on the American side, some of them freed for it by their states. Pennsylvania passed a law for gradual abolition in 1780 and other northern states followed, but slavery survived in the South and was protected in the new nation's founding law.

Most Native nations sided with Britain, which had tried since 1763 to stop colonists settling west of the Appalachians. The Iroquois Confederacy split: four of its six nations fought for Britain and the Oneida and Tuscarora mostly for the Americans. The Treaty of Paris handed the land between the Appalachians and the Mississippi to the United States without consulting the nations who lived on it.

An estimated 6,800 Americans were killed in action, and at least 17,000 more died of disease, including thousands who died as prisoners of war.

What is the difference between the war and the Revolution?

The war was the fighting from 1775 to 1783. The American Revolution was the larger change: a break from monarchy, the Declaration of Independence, which justified independence by the claim that governments get "their just powers from the consent of the governed", new state constitutions, the Articles of Confederation, and finally the US Constitution of 1787. John Adams, looking back in 1818, wrote that "the Revolution was effected before the war commenced", in the changed minds of the colonists.

Its ideas traveled. France's spending on the war deepened the debt that helped bring on the French Revolution in 1789, and the Declaration became a model for movements for independence and self-government in the two centuries since. The Declaration's 250th anniversary fell on 4 July 2026.

Still argued

Historians have long argued about what the Revolution was. Some stress ideas: a genuine conviction that British rule threatened liberty. Others stress interests: merchants' profits, land speculators blocked from the West, and planters' fear that Britain would threaten slavery, a claim that is itself much debated. More recent work asks how revolutionary it was for women, enslaved people and Native nations, for whom the new republic brought little or no freedom. Most historians now hold several of these views together, as history usually does.

Check yourself

• What did "no taxation without representation" mean, and what was Parliament's answer to it?
• Why could the Americans lose most of the battles and still win the war?
• Explain how Saratoga led to Yorktown, through France.

Sources

• Parliamentary taxation of colonies, international trade, and the American Revolution, 1763–1775 — Office of the Historian, U.S. Department of State
• French Alliance, French Assistance, and European Diplomacy during the American Revolution, 1778–1782 — Office of the Historian, U.S. Department of State
• Treaty of Paris, 1783 — Office of the Historian, U.S. Department of State
• American Revolution FAQs — American Battlefield Trust
• The Declaration of Independence — U.S. National Archives