New York State Route 108 (NY 108) is a north–south state highway located on the Suffolk County side of the Suffolk–Nassau county line on Long Island, New York, in the United States. It is a spur route connecting NY 25A in Cold Spring Harbor to the Cold Spring Harbor station on the Long Island Rail Road's Port Jefferson Branch via Harbor Road. Harbor Road terminates at an intersection with Woodbury Road, on the Nassau County line, which carries County Route 11 to the east and unsigned County Route 12 to the west. NY 108, assigned in the early 1930s, is the shortest state highway on Long Island.