New York State Route 631 (NY 631) is a north–south state highway in Onondaga County, New York, in the United States. It serves as a bypass around the village of Baldwinsville, extending for just over 5 miles (8.0 km) from an intersection with NY 370 in the southeastern part of the village to a junction with NY 48 and NY 690 just north of Baldwinsville in the town of Lysander. The route has a short overlap with NY 31 east of the village. Most of the route is two lanes wide and passes through rural areas around the edge of Baldwinsville, while a part near the Lysander community of Radisson is four lanes wide and serves residential and commercial neighborhoods.