In 2020, St. Clair County, IL had a population of 261k people with a median age of 39.1 and a median household income of $57,473. Between 2019 and 2020 the population of St. Clair County, IL declined from 262,338 to 261,186, a −0.439% decrease and its median household income grew from $55,179 to $57,473, a 4.16% increase.
The 5 largest ethnic groups in St. Clair County, IL are White (Non-Hispanic) (61%), Black or African American (Non-Hispanic) (29.7%), Two+ (Non-Hispanic) (3.09%), White (Hispanic) (2.16%), and Asian (Non-Hispanic) (1.42%).
None of the households in St. Clair County, IL reported speaking a non-English language at home as their primary shared language. This does not consider the potential multi-lingual nature of households, but only the primary self-reported language spoken by all members of the household.
98.5% of the residents in St. Clair County, IL are U.S. citizens.
The largest universities in St. Clair County, IL are Southwestern Illinois College (2,016 degrees awarded in 2020) and McKendree University (691 degrees).
In 2020, the median property value in St. Clair County, IL was $134,800, and the homeownership rate was 65.9%.
Most people in St. Clair County, IL drove alone to work, and the average commute time was 25.4 minutes. The average car ownership in St. Clair County, IL was 2 cars per household.
St. Clair County, IL borders Clinton County, IL, Madison County, IL, Monroe County, IL, Randolph County, IL, Washington County, IL, St. Louis County, MO, and St. Louis city, MO.