New York State Route 31 (NY 31) is a state highway that extends for 208.74 miles (335.93 km) across western and central New York in the United States. The western terminus of the route is at an intersection with NY 104 in the city of Niagara Falls. Its eastern terminus is at a traffic circle with NY 26 in Vernon Center, a hamlet within the town of Vernon. Over its routing, NY 31 spans 10 counties and indirectly connects three major urban areas in Upstate New York: Buffalo–Niagara Falls, Rochester, and Syracuse. The route is one of the longest routes in New York State, paralleling two similarly lengthy routes, NY 104 to the north and NY 5 to the south, as well as the Erie Canal, as it proceeds east.