The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, was the armed conflict that comprised the final eight years of the broader American Revolution, in which American Patriot forces organized as the Continental Army and commanded by George Washington defeated the British Army. The conflict was fought in North America, the Caribbean, and the Atlantic Ocean. The war's outcome seemed uncertain for most of the war. But Washington and the Continental Army's decisive victory in the Siege of Yorktown in 1781 led King George III and the Kingdom of Great Britain to negotiate an end to the war in the Treaty of Paris two years later, in 1783, in which the British monarchy acknowledged the independence of the Thirteen Colonies, leading to the establishment of the United States as an independent and sovereign nation.

In 1763, after the British Empire gained dominance in North America following its victory over the French in the Seven Years' War, tensions and disputes began escalating between the British and the Thirteen Colonies, especially following passage of Stamp and Townshend Acts. The British Army responded by seeking to occupy Boston militarily, leading to the Boston Massacre on March 5, 1770. In mid-1774, with tensions escalating even further between the British Army and the colonies, the British Parliament imposed the Intolerable Acts, an attempt to disarm Americans, leading to the Battles of Lexington and Concord in April 1775, the first battles of the Revolutionary War. In June 1775, the Second Continental Congress voted to incorporate colonial-based Patriot militias into a central military, the Continental Army, and unanimously appointed Washington its commander-in-chief. Two months later, in August 1775, the British Parliament declared the colonies to be in a state of rebellion. In July 1776, the Second Continental Congress formalized the war, passing the Lee Resolution on July 2, and, two days later, unanimously adopting the Declaration of Independence, on July 4.

In March 1776, in an early win for the newly-formed Continental Army under Washington's command, following a successful siege of Boston, the Continental Army successfully drove the British Army out of Boston. British commander in chief William Howe responded by launching the New York and New Jersey campaign, which resulted in Howe's capture of New York City in November. Washington responded by clandestinely crossing the Delaware River and winning small but significant victories at Trenton and Princeton.

In the summer of 1777, as Howe was poised to capture Philadelphia, the Continental Congress fled to Baltimore. In October 1777, a separate northern British force under the command of John Burgoyne was forced to surrender at Saratoga in an American victory that proved crucial in convincing France and Spain that an independent United States was a viable possibility. France signed a commercial agreement with the rebels, followed by a Treaty of Alliance in February 1778. In 1779, the Sullivan Expedition undertook a scorched earth campaign against the Iroquois who were largely allied with the British. Indian raids on the American frontier, however, continued to be a problem. Also, in 1779, Spain allied with France against Great Britain in the Treaty of Aranjuez, though Spain did not formally ally with the Americans.

Howe's replacement Henry Clinton intended to take the war against the Americans into the Southern Colonies. Despite some initial success, British General Cornwallis was besieged by a Franco-American army in Yorktown, Virginia in September and October 1781. The French navy cut off Cornwallis's escape and he was forced to surrender in October. The British wars with France and Spain continued for another two years, but fighting largely ceased in North America. In the Treaty of Paris, signed on September 3, 1783, Great Britain acknowledged the sovereignty and independence of the United States, bringing the American Revolutionary War to an end. The Treaties of Versailles resolved Great Britain's conflicts with France and Spain, and forced Great Britain to cede Tobago, Senegal, and small territories in India to France, and Menorca, West Florida, and East Florida to Spain.

The French and Indian War, part of the wider global conflict known as the Seven Years' War, ended with the 1763 Peace of Paris, which expelled France from their possessions in New France. The Royal Proclamation of 1763 was designed to refocus colonial expansion north into Nova Scotia and south into Florida, with the Mississippi River as the dividing line between British and Spanish possessions in America. Settlement was tightly restricted beyond the 1763 limits, and claims west of this line, including by Virginia and Massachusetts, were rescinded. With the exception of Virginia and others deprived of rights to western lands, the colonial legislatures agreed on the boundaries but disagreed on where to set them. Many settlers resented the restrictions entirely, and enforcement required permanent garrisons along the frontier, which led to increasingly bitter disputes over who should pay for them.

The huge debt incurred by the Seven Years' War and demands from British taxpayers for cuts in government expenditure meant Parliament expected the colonies to fund their own defense. The 1763 to 1765 Grenville ministry instructed the Royal Navy to cease trading smuggled goods and enforce customs duties levied in American ports. The most important was the 1733 Molasses Act; routinely ignored before 1763, it had a significant economic impact since 85% of New England rum exports were manufactured from imported molasses. These measures were followed by the Sugar Act and Stamp Act, which imposed additional taxes on the colonies to pay for defending the western frontier. The taxes proved highly burdensome, particularly for the poorer classes, and quickly became a source of discontent. In July 1765, the Whigs formed the First Rockingham ministry, which repealed the Stamp Act and reduced tax on foreign molasses to help the New England economy, but re-asserted Parliamentary authority in the Declaratory Act.

However, this did little to end the discontent; in 1768, a riot started in Boston when the authorities seized the sloop Liberty on suspicion of smuggling. Tensions escalated in March 1770 when British troops fired on rock-throwing civilians, killing five in what became known as the Boston Massacre. The Massacre coincided with the partial repeal of the Townshend Acts by the Tory-based North Ministry. North insisted on retaining duty on tea to enshrine Parliament's right to tax the colonies; the amount was minor, but ignored the fact it was that very principle Americans found objectionable.