The Siege of Yorktown was a crucial battle during the American Revolutionary War that took place in 1781. It marked the last major conflict between the American colonists and the British forces. Led by General George Washington, the American and French troops surrounded the British army, commanded by General Cornwallis, cutting off their supplies and escape routes. After weeks of intense fighting, Cornwallis realized he could not win and surrendered on October 19, 1781. This victory was significant because it boosted American morale and led to negotiations for peace, ultimately resulting in the independence of the United States from British rule.