The war that created the United States was, at its core, the product of a relationship that had grown intolerably strained over more than a decade before a single shot was fired. In 1763, Britain emerged from the Seven Years' War as the dominant power in North America, having expelled France from Canada and secured vast new territories. But victory came with an enormous debt, and Parliament decided that the American colonies — which had benefited directly from British military protection — should help pay for it.
The resulting taxation policies produced outrage in the colonies, where the doctrine of no taxation without representation had deep roots. The Stamp Act and Townshend Acts provoked protests, boycotts, and eventually violence. On March 5, 1770, tensions boiled over in Boston when British soldiers fired into a crowd, killing five civilians in what colonists quickly labeled the Boston Massacre. The killing of peaceful civilians by occupation troops became a powerful piece of propaganda in the growing resistance movement. When Parliament imposed the Intolerable Acts in mid-1774 — punitive measures designed to crush colonial dissent and disarm the Americans — the colonies began moving toward open confrontation.
The war began in earnest on April 19, 1775, with the Battles of Lexington and Concord in Massachusetts, where colonial militiamen clashed with British regulars who had been dispatched to seize colonial arms. The fights were small, but their symbolic resonance was enormous. News of the engagements spread through the colonies within days, and men took up arms across New England. In June 1775, the Second Continental Congress voted to unify the various colonial militias into a central force, the Continental Army, and unanimously appointed George Washington as its commander-in-chief. Two months later, in August, King George III formally declared the colonies to be in a state of rebellion, closing the door on any negotiated resolution.
In March 1776, Washington demonstrated his strategic creativity by secretly moving captured cannon onto the heights overlooking Boston Harbor, threatening to destroy the British fleet in port. The British commander, General William Howe, had no choice but to evacuate his forces by sea. It was an early and badly needed American victory. But Howe struck back hard, launching the New York and New Jersey campaign that captured New York City in November 1776 and nearly destroyed the Continental Army entirely. Washington's response — a daring nighttime crossing of the ice-choked Delaware River on December 25 — led to surprise victories at Trenton and Princeton that revived colonial morale at a critical moment.
The decisive turning point came in October 1777, in the forests of upstate New York, where a British force under General John Burgoyne was surrounded and forced to surrender at Saratoga. The victory was more than a battlefield success; it was a diplomatic earthquake. France, which had been cautiously supplying the Americans with money and supplies, was now convinced that an independent United States was a realistic possibility. A commercial agreement was signed, followed by a Treaty of Alliance in February 1778 that brought France openly into the war against Britain. In 1779, Spain allied with France against Great Britain through the Treaty of Aranjuez, though it did not formally ally with the American rebels. The war had become a global conflict.
The southern theater became the new British focus in 1780 and 1781, as General Henry Clinton sought to exploit Loyalist support in the Carolinas and Virginia. Initial British successes gave way to a grinding guerrilla war, and General Charles Cornwallis found himself maneuvered into an increasingly exposed position at Yorktown, Virginia. A Franco-American army converged on Yorktown from the north while the French fleet under Admiral de Grasse defeated the British navy at the Battle of the Chesapeake in September 1781, cutting off Cornwallis's escape by sea. Besieged on land and blockaded from the water, Cornwallis was forced to surrender his army of approximately 8,000 men on October 19, 1781. It was the last major engagement of the war in North America.
Britain continued fighting France and Spain in other theaters for another two years, but the political will to press on against the American colonies had collapsed. Negotiations began in Paris, and on September 3, 1783, the Treaty of Paris formally ended the war. Britain acknowledged the independence of the thirteen former colonies and recognized the sovereignty of the new United States over territory stretching from the Atlantic coast to the Mississippi River. What had begun as a tax dispute had produced a new nation and a political philosophy — rooted in natural rights, representative government, and constitutional restraint — that would reshape political thought across the world for centuries to come.
