On September 11, 1777, the Battle of Brandywine, Pennysylvania took place.
"On September 11, 1777, General George Washington was determined to prevent the British from capturing the American seat of government, Philadelphia. Taking up positions along Brandywine Creek, Washington mistakenly believed that his army blocked all fords across the Brandywine.
Opposing Washington was Sir William Howe and an army of 15,500 British Regulars and Hessian troops. Hidden by heavy fog, the British moved into position. General Wilhelm von Kynphausen was ordered to demonstrate against the Americans’ front at Chadds Ford, while the bulk of Howe’s forces crossed the Brandywine further upstream."