While general John Burgoy
While general John Burgoyne moved towards New York from Canada  General William Howe sailed to the Chesapeake and started moving  towards Philadelphia with a force of 15,000 men. On September 11  Howe met the forces of Washington and attcked and was able to  overwhelm the right flank held by General John Sullivan, resulting  in a total defeat for the Continental forces. For 10 points name  this battle in which Washington lost a tenth of his 10,500 man army  fought by a body of water in Southern Pennsylvainia.
While general John Burgoyne moved towards New York from Canada  General William Howe sailed to the Chesapeake and started moving  towards Philadelphia with a force of 15,000 men.
Brandywine Creek