Monroe County Flag

Monroe County

State:
Illinois
County Seat:
Waterloo

Monroe County's estimated 2025 population is 34,794 with a growth rate of -0.5% in the past year according to the most recent United States census data. Monroe County is the 40th largest county in Illinois. The 2010 population was 33,051 and has seen a growth of 5.27% since that time.

34,794
Total Population
90
Population Density (mi²)
40
Population Rank (State)
-175 -0.5%
Annual Population Growth

Monroe 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)