The Continental (American) Army under George Washington was encamped in Bergen County from August 23 to September 20, 1780. The historic sign here explains the role played by this location during the latter part of this encampment:
"The Continental Army advanced to Englewood on August 23, 1780, with some units foraging as far south as Jersey City. The main body of the army moved west of the Hackensack River on September 4th, camping in two lines west of Kinderkamack Road, one atop the ridge and one below. The camp extended from River Edge Road two miles north to the vicinity of Soldier Hill. The artillery park was near their center along Ridgewood Avenue. Light infantry was posted on the heights behind New Bridge in Van Saun Co. Park. Lafayette had his headquarters at the north end of the encampment, near this spot. The army departed on September 20, 1780." 
1.^ Bergen County Historical Society historic marker
Revolutionary War New Jersey
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Soldier Hill • Lafayette Encampment