Washington does not know where Howe is…
August 1777 CE
Considering the possibility that Howe is again feinting, and will actually sail his army up the Hudson to join with Burgoyne, he remains near New York.
Only when he receives word that Howe's fleet has reached the mouth of the Delaware, does he need to consider the defense of Philadelphia.
However, the fleet does not enter the Delaware, instead continuing south.
Uncertain of Howe's goal, which could be Charleston, South Carolina, he considers moving north to assist in the defense of the Hudson, when he learns that the fleet had entered Chesapeake Bay.
In August, he begins moving his troops south to prepare the city's defenses.
General John Sullivan, who commands the Continental Army's troops facing Staten Island, had, in order to capitalize on perceived weaknesses of the British position there following Howe's departure, attempted a raid on August 22, that had failed with the Battle of Staten Island.
Sullivan's forces march south after the battle, and are able to join Washington's defensive arrangements south of Philadelphia in time to participate in the key Battle of Brandywine on September 11.
General Sullivan will later be subjected to a court martial over accusations that he mismanaged the expedition in a variety of ways.
The court will exonerate him of all charges.