Marion   County IL United States

County FIPS 17121
Largest City Centralia
State Illinois
Latitude 38.6496
Longitude -88.9190
Population 37,000
Density 64.64 people per square mile
Time Zone America/Chicago
  • All demographic data comes from the 2024 American Community Survey (5-year study).
  • Learn more about each field.
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Household Income

Median household: $61,240
Median individual: $35,650

Race

Mode: 89.9% White

Gender

 50.8% female 

Rent

  $794 / month  

Median house value: $101,568.0

Age

Median: 41.5 years old

Education

With at least college degree: 16.8%
With STEM degree: 36.6%

Marital Status

 48.2% married 

Never married: 28.1%

Labor Force Participation

 60.1% working 

Unemployed: 5.9%

Average Family Size

 2.99 people 

Commute Time

 21.1 minutes 

Health Care

 6.4% uninsured 

Poverty

 15.4%

All data comes from the SimpleMaps US Counties Database, 2026.

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