The Siege of Yorktown forced Lord Cornwallis to surrender in 1781.
The Franco-American operation began on September 28, 1781, when forces commanded by George Washington and the Comte de Rochambeau surrounded the British army at Yorktown, Virginia. Cornwallis commanded roughly 8,000 British and German troops.
French naval control of the Chesapeake Bay prevented the British from evacuating or reinforcing Cornwallis. American and French troops built successive siege lines and bombarded the British positions. Cornwallis surrendered on October 19, 1781, after weeks of encirclement.
Yorktown was the final major land engagement of the American Revolutionary War, although fighting and diplomacy continued afterward. The surrender greatly weakened Britain’s political support for continuing the conflict and led to peace negotiations. The war formally ended with the 1783 Treaty of Paris, a separate event from the 1781 siege.