The Boston Post Road Historic District is a historic district including 3 pre-civil war mansions and their grounds, a 10,000 year old Paleo-Indian meadow and viewshed, a cemetery, and a nature preserve. It touches on the south side of the nation's oldest road Boston Post Road (US 1) in Rye, New York where mile marker “24” out of 230, designated in 1763 by Benjamin Franklin, is set into the perimeter wall; from there the landmarked area of 286 acres (1.16 km²) expands down to the Milton Harbor of the Long Island Sound.