05/31/2026
Do you know Major John Clark Jr.? When the British occupied Philadelphia in September 1777, George Washington needed eyes inside and around the city.
That responsibility fell in part to Major John Clark Jr., a Pennsylvania officer who helped operate Washington’s intelligence network during the Philadelphia campaign.
Clark’s agents and couriers reported on British troop movements, wagons, ammunition, river activity, bridge construction, ships, and rumored attacks. In November 1777, his reports helped Washington follow British operations around the Delaware River forts, including Fort Mifflin and Fort Mercer, which blocked British control of the river south of Philadelphia. 
Clark’s work depended on informants, concealed letters, couriers, and sources willing to move through occupied territory. One surviving report from November 3, 1777 described ammunition wagons, British positions, bridge-building, shipping, and plans to attack the forts. 
His story is a reminder that Revolutionary War intelligence was not only carried through New York coffee houses or Long Island. Intelligence was vital in all areas of the War.