Wellsville is a village in Allegany County, New York, United States. Located in south-central wooded and rural Allegany County, it is the largest population and business center in a 30-mile radius. The population was 4,679 at the 2010 census. The village's name is not, as some suppose, derived from the oil wells that became an important economic part of the area, but rather for Gardiner Wells, a local businessman.