Which 1781 battle was the last major military conflict of the American Revolutionary War?

The Siege of Yorktown was the last major military conflict of the American Revolutionary War.

American and French forces surrounded the British army commanded by General Charles Cornwallis at Yorktown, Virginia, in September and October 1781. General George Washington led the American army, while French troops and the French fleet played decisive supporting roles.

The siege ended when Cornwallis surrendered on October 19, 1781. The defeat badly weakened Britain's political support for continuing the war, although smaller military actions and diplomatic negotiations continued afterward.

Yorktown did not itself create American independence in law. That status was recognized by the Treaty of Paris, signed in 1783. The battle is also sometimes called the Battle of Yorktown, but “Siege of Yorktown” is the specific name for the wider land and naval operation that forced the British surrender.