Marion County Flag

Marion County

State:
Illinois
County Seat:
Salem

Marion County's estimated 2025 population is 36,234 with a growth rate of -0.56% in the past year according to the most recent United States census data. Marion County is the 37th largest county in Illinois. The 2010 population was 39,416 and has seen a growth of -8.07% since that time.

36,234
Total Population
63
Population Density (mi²)
37
Population Rank (State)
-203 -0.56%
Annual Population Growth

Marion County Population

Demographics

Economics and Income Statistics

Sources

  1. City and Town Population Totals: 2020-2024
  2. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  3. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  4. American Community Survey (2009 - 2013)
  5. Census QuickFacts
  6. Historical Populations of States and Counties (1790 - 1990)