Mason County, Illinois

Mason County is a county in Illinois with an estimated population of 12,523 in 2023. 7 cities, towns and Census places in it are indexed here.

Largest places in Mason County

About Mason County

Mason County is one of the counties of Illinois. County governments in Illinois handle local services such as courts, property records and elections; cities and towns inside the county run their own municipal services. Population figures come from the Census Bureau's Vintage 2023 estimates, which are updated annually.