Guilford Courthouse
Yorktown
Because they were going to lose the war.
General Cornwallis set up camp @ Yorktown October 1781
Yorktown
Yorktown
Cornwallis did, assuming that's the battle your talking about. Nathaniel Greene sent Cornwallis on a chase, because he just kept retreating deeper and deeper into the colonies. Cornwallis was called back, and he ended up in Yorktown, thinking that this was a wise move because he had the coast to his back, and therefore he could only be attacked on one side. But instead he ended up being surrounded by the French Navy and the continental army. Not such a good idea after all.
During the Siege of Yorktown, Cornwallis and his men ended up being completely surrounded by U.S. and French troops, both army and navy. Cornwallis had no choice but to surrender. Over 7,000 British troops were captured in the siege.
He was surrounded and there was noway for him to win so he gave up. NOTE he had someone who was supposed to help him, but by the time they got around to it it was to late.
Sami sarrouj's house
General Cornwallis
Yorktown was on the water on one side, so the British army could not escape the large American/French army that was bombarding them. Rather than let his soldiers die, their commander, Cornwallis, elect to surrender. Cornwallis had pleaded for help from General Clinton's ships up in New York, but Clinton would not hurry for anybody, and so the ships made it to Yorktown a couple of days after Cornwallis had surrendered.