The city of Marion is the county seat of Williamson County, Illinois, United States. The population in the Marion city, IL was 16,867 per American Community Survey data for 2018-2022.
Marion clock tower in the town square
Marion in 1938
Marion, 1910
Williamson County Courthouse
Williamson County, Illinois
Williamson County is a county in Southern Illinois. At the 2020 census, it had a population of 67,153. The largest city and county seat is Marion.
Williamson County Courthouse in Marion