Why might general cornwallis's choice of yorktown as a base have left him at a military disadvantage

When the British retired to New York leaving control of the Chesapeake Bay in the hands of the French, General Cornwallis found his troops without provisions and with the American and French armies besieging them. After three weeks of being besieged by the Americans and the French, and after failing to flee the York River, the general and his troops had to surrender on October 19, 1781. The Battle of Yorktown was the the last major battle during the Revolutionary War, with which General Cornwallis went down in history as the general who lost the American Colonies.