Williamsville is a village in Sangamon County, Illinois, United States.

The village is named after Springfield merchant and banker John Williams.

[2] According to the 2010 census, Williamsville has a total area of 1.26 square miles (3.26 km2), all land.

[3] The Williamsville-Sherman CUSD15 office is located at 800 S. Walnut St., Williamsville, IL 62693 As of the census[5] of 2000, there were 1,439 people, 531 households, and 417 families residing in the village.

19.4% of all households were made up of individuals, and 9.0% had someone living alone who was 65 years of age or older.