Williamson is a village in Madison County, Illinois, United States.

[5] The village is named for the land's original owners, John and Matthew Williamson.

[6] Williamson is bordered to the south by the village of Livingston and to the north by Macoupin County.

Interstate 55 passes just east of the village, with access from Exit 37 in Livingston.

26.3% of all households were made up of individuals, and 18.2% had someone living alone who was 65 years of age or older.