On May 31, 1771, Hillsborough was officially granted a Charter incorporating it as a Township. A revised charter was issued on September 12, 1771. The records of Hillsborough Township are complete from their inception in 1746 and there are ten volumes, each some several hundred pages, kept in the Special Collections Department of the Rutgers University Library along with the Charter.
Hillsborough Township quickly took its place in history as the path General George Washington and his troops traveled from the Battle of Princeton to winter quarters in Morristown. While the British were encamped in the valley below awaiting an opportunity to attack, it is said that Washington drilled his troops on the Sourland Mountain around a spring near the top using different formations and corn stalks for guns. As the sun caught the stalks, the British thought Washington had received reinforcements and fresh supplies and the British troops, thinking that they were outnumbered, slipped off to New Brunswick leaving Washington to continue to Morristown.
Hillsborough Township was formally incorporated on February 21, 1798.
Hillsborough is also home to Duke Gardens and Duke Farms, a 2,700 acre (11 km²) estate in the north-eastern quadrant of the town. Originally owned by tobacco and electric energy tycoon, James "Buck" Duke and then passed down to daughter Doris Duke, Duke Farms is now one of the few remaining "preserved" natural areas in Hillsborough Township.
