British forces surrendered at Yorktown on October 19, 1781, ending the final major land engagement of the American Revolutionary War.
The allied American and French armies had trapped Lieutenant General Charles Cornwallis's army on Virginia's Yorktown Peninsula. George Washington commanded the American forces, while Rochambeau led the French army units supporting the operation. French naval control of the Chesapeake helped prevent Cornwallis from escaping by sea.
The siege began in September 1781, and allied artillery gradually weakened the British position. Cornwallis surrendered after failed attempts to break through the encircling lines. The surrender was a major military victory, although smaller fighting and diplomatic negotiations continued afterward.
The war formally ended with the Treaty of Paris in 1783. Yorktown is therefore best described as the decisive final major campaign, not the legal conclusion of the war itself.