After defeating the Continental Army at the Battle of Brandywine on September 11, and the Battle of Paoli on September 20, Howe outmaneuvered Washington, seizing Philadelphia, the capital of the United States, on September 26. Howe left a garrison of some 3,000 troops in Philadelphia, while moving the bulk of his force to Germantown, then an outlying community to the city. Learning of the division, Washington determined to engage the British. His plan called for four separate columns to converge on the British position at Germantown. The two flanking columns were composed of 3,000 militia, while the center-left, under Nathanael Greene, the center-right under John Sullivan, and the reserve under Lord Stirling were made up of regular troops. The ambition behind the plan was to surprise and destroy the British force, much in the same way as Washington had surprised and decisively defeated the Hessians at Trenton. In Germantown, Howe had his light infantry and the 40th Foot spread across his front as pickets. In the main camp, Wilhelm von Knyphausen commanded the British left, while Howe himself personally led the British right.
A heavy fog caused a great deal of confusion among the approaching Americans. After a sharp contest, Sullivan’s column routed the British pickets. Unseen in the fog, around 120 men of the British 40th Foot barricaded the Chew Mansion. When the American reserve moved forward, Washington made the erroneous decision to launch repeated assaults on the position, all of which failed with heavy casualties. Penetrating several hundred yards beyond the mansion, Sullivan’s wing became dispirited, running low on ammunition and hearing cannon fire behind them. As they withdrew, Anthony Wayne’s division collided with part of Greene’s late-arriving wing in the fog. Mistaking each other for the enemy, they opened fire, and both units retreated. Meanwhile, Greene’s left-center column threw back the British right. With Sullivan’s column repulsed, the British left outflanked Greene’s column. The two militia columns had only succeeded in diverting the attention of the British, and had made no progress before they withdrew.
Despite the defeat, France, already impressed by the American success at Saratoga, decided to lend greater aid to the Americans. Howe did not vigorously pursue the defeated Americans, instead turning his attention to clearing the Delaware River of obstacles at Red Bank and Fort Mifflin. After unsuccessfully attempting to draw Washington into combat at White Marsh, Howe withdrew to Philadelphia. Washington, his army intact, withdrew to Valley Forge, where he wintered and re-trained his forces.