 New York State Route 120 ( NY 120 ) is a state highway in southern Westchester County , New York , in the United States . It begins in the city of Rye at an intersection with U.S. Route 1 ( US 1 ) and runs for about 18 miles ( 29 km ) north to the hamlet of Millwood , where it ends at an intersection with NY 100 . NY 120 is a two-lane road for most of its length, but has a four-lane section between the city of Rye and the hamlet of Rye Brook . The route was assigned in the early 1930s, and