Who surrendered to Washington at 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.