New York State Route 56 (NY 56) is a north–south state highway in eastern St. Lawrence County, New York, in the United States. The southern terminus of the route is at an intersection with NY 3 in the town of Colton. Its northern terminus is at a junction with NY 37 southwest of Massena in the town of Louisville. NY 56 follows the Raquette River for most of its length and serves the village of Potsdam, where it passes by the campus of Clarkson University.