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.

New York State Route 104 (NY 104) is a 182.41-mile-long (293.56 km) east–west state highway in Upstate New York in the United States. It spans six counties and enters the vicinity of four cities—Niagara Falls, Lockport, Rochester, and Oswego—as it follows a routing largely parallel to the southern shoreline of Lake Ontario, along a ridge of the old shoreline of Glacial Lake Iroquois. The western terminus of NY 104 is an intersection with NY 384 in Niagara Falls, Niagara County, while its eastern terminus is a junction with NY 13 in the town of Williamstown, Oswego County. The portion of NY 104 between Rochester and the village of Webster east of the city is a freeway known as the Keeler Street Expressway west of NY 590 and the Irondequoit–Wayne County Expressway east of NY 590; from Williamson to Oswego, NY 104 is a super two highway.