 Although most closely associated with Henry Knox, who used it as his headquarters as the Revolutionary War drew to a close in the early 1780s, it was used as a general's headquarters throughout most of the war, by Nathanael Greene and Horatio Gates.The site was declared a National Historic Landmark in 1972.While owned by the New York State Office of Parks, Recreation and Historic Preservation the Ellison House is administered and operated by the Palisades Interstate Park Commission, like many other state parks and historic sites in the mid and lower Hudson region.