Williamsville is a village in Erie County, New York in the United States. The population was 5,573 at the 2000 census. The village is named after Jonas Williams, an early settler. It is part of the Buffalo–Niagara Falls Metropolitan Statistical Area. Williamsville is located mostly within the town of Amherst, but Creek Road and Creek Heights in the south part of the village are in the town of Cheektowaga. The village is in the northeastern quadrant of Erie County. Williamsville is also a postal ZIP code: 14221 (14231 for PO Boxes); however, that zip code contains large sections of the town outside of the village and also includes significant commercial areas within Clarence.