The Battle of Yorktown was important to the American Revolution because it ended in the surrender of the General Cornwallis and his army, effectively ending the war in the American colonies. The battle took place between Sept. 28th and Oct. 19, 1781 at Yorktown, Virginia.
General George Cornwallis, the British commander of an army of 9,000 men, chose the city of Yorktown as his headquarters. Upon hearing this, George Washington, the leader of the American army, decided to strike. The American army encircled Yorktown, blocking Cornwallis' retreat by land, and a large French fleet cut off his ability to retreat by sea. The French and American forces bombarded the British positions nonstop for three weeks. This bombardment, along with the unfortunate outbreak of smallpox and some bad weather, forced Cornwallis to begin negotiating a surrender.
After the British surrender on October 19th, there was little political will in the British government to continue waging war in the colonies. In Parliament, the American victory caused the fall of Lord North's government, allowing a more pro-American government to come to power. Although the war continued on the ocean and in other colonies, hostilities in the 13 colonies came to an end. The major combatants began discussing terms for a treaty in Paris in April 1782, and they eventually signed the Treaty of Paris on Sept. 3, 1783, officially ending the war.