Which battle in October 1781 effectively ended the American Revolutionary War?

The Battle of Yorktown, fought in October 1781, effectively ended the American Revolutionary War.

The decisive operation was the Siege of Yorktown in Virginia, where American forces under George Washington and French forces under the Comte de Rochambeau surrounded the British army commanded by General Charles Cornwallis. French naval forces also helped prevent British reinforcement or escape by sea.

Cornwallis surrendered on October 19, 1781. Fighting and diplomatic negotiations continued afterward, but the defeat made continued British efforts to regain the American colonies politically difficult and militarily impractical.

The war formally ended with the Treaty of Paris, signed in 1783. Yorktown is therefore best described as the conflict’s decisive final major battle, rather than the exact legal end of the war. The alliance with France was crucial to the American victory.