Yorktown was the American military victory that led to the British surrender at the end of the Revolutionary War.
The Siege of Yorktown took place in Virginia from September 28 to October 19, 1781. American forces commanded by George Washington and French forces commanded by the Comte de Rochambeau surrounded the British army led by Lord Cornwallis.
French naval forces helped prevent British relief by defeating or blocking the British fleet in the Chesapeake Bay. After artillery bombardment and trench operations weakened the British position, Cornwallis surrendered on October 19. The military defeat effectively ended major combat, although the formal peace treaty came later.
Yorktown is sometimes described as the end of the war itself, but the Treaty of Paris was the legal settlement signed in 1783. The victory nevertheless changed British political calculations and opened the way for serious peace negotiations.