Monroe County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 40th-largest in Illinois
The population of Monroe County, Illinois is 34,969 as of the 2023 American Community Survey, making it the 40th-largest county in Illinois. The median household income is $101,635, the median home value is $265,600, and the median age is 42.5.
The population of Monroe County has grown 5.8% since 2010 (33,051 → 34,969), a +0.40% annualized rate.
34,969
Population
+0.40%
Annual growth
91
People / sq mi
$101,635
Median Income
$265,600
Median Home Value
Monroe County covers 385 sq mi of land at 90.8 people per square mile.
About Monroe County, IL
Monroe County is a county in Illinois with a population of 34,969. It ranks #40 among counties in Illinois by population. The median age is 42.5, older than the national median. The population is 50.4% male and 49.6% female.
The median household income in Monroe County is $101,635, above the US median of $74,580. 3.7% of residents live below the federal poverty level. Home values sit at a median of $265,600, with monthly rent averaging $996. The homeownership rate of 83.8% is higher than the national rate of 64.8%.
Educational attainment in Monroe County reflects 38.2% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 11.6% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 28.3 minutes each way.
Monroe County Population History (2010-2024)
The county of Monroe County had a population of 33,051 in 2010 and 34,969 in 2024, a 5.8% growth over 14 years. The peak was 35,144 in 2023. Average annual growth rate: 0.40%.
34,969
Population (2024)
33,051
Population (2010)
35,144
Peak (2023)
0.40%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 33,051 |
| 2011 | 33,273 |
| 2012 | 33,320 |
| 2013 | 33,523 |
| 2014 | 33,608 |
| 2015 | 33,811 |
| 2016 | 34,037 |
| 2017 | 34,261 |
| 2018 | 34,446 |
| 2019 | 34,738 |
| 2020 | 34,953 |
| 2021 | 35,007 |
| 2022 | 35,107 |
| 2023 | 35,144 |
| 2024 | 34,969 |
Race & Ethnicity
| White | 96.1% |
| Black or African American | 0.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.5% |
| Two or More Races | 0.0% |
Age & Sex
42.5
Median Age
49.6%
Female
50.4%
Male
18.9%
Age 65+
Age Distribution
Children (under 15): 18.1% · Seniors (65+): 18.9%
Income & Poverty
| Median household income | $101,635+$19,933 vs state |
| Mean household income | $122,572 |
| Per-capita income | $49,438 |
| Poverty rate | 3.7%-4.5% vs state |
| Unemployment rate | 1.4% |
| Employment-to-population | 66.9% |
Top Industries by Employment
The largest employment sector in Monroe County is professional & business services, accounting for 23.2% of workers.
How residents commute
0.0%
Drive alone
1.2%
Carpool
81.1%
Public transit
11.6%
Work from home
28.3 min
Avg commute
Housing
$265,600+$15,100 vs state
Median home value
$996
Median rent
83.8%
Homeownership rate
14,665
Total housing units
94.3%
Occupied
5.7%
Vacant
16.2%
Renter-occupied
Social & access
97.8%
With health insurance
93.7%
With broadband internet
43.7%
Foreign-born
8.5%
Veterans (18+)
10.7%
With a disability
98.2%
Speak language other than English at home
Education
95.8%
High School+
38.2%
Bachelor's+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
County rankings
Frequently Asked Questions
Monroe County, Illinois has a population of 34,969 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 40th-largest county in Illinois. Population density is 91 people per square mile.
The population of Monroe County has grown 5.8% since 2010 (33,051 → 34,969), a +0.40% annualized rate.
The median household income in Monroe County, Illinois is $101,635, with mean (average) household income of $122,572 and per-capita income of $49,438. 3.7% of residents live below the federal poverty level.
In Monroe County, the largest racial and ethnic groups are White (96.1%), Black or African American (0.6%), Hispanic or Latino (0.5%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Monroe County, Illinois is 42.5 years. Residents are 49.6% female and 50.4% male.
The median home value in Monroe County is $265,600 and median monthly rent is $996. 83.8% of occupied housing units are owner-occupied. The county has 14,665 total housing units, 5.7% of which are vacant.
The largest employment sector in Monroe County, Illinois is professional, scientific, and management services, employing 23.2% of workers. The unemployment rate is 1.4%.
Chicago is among the largest cities associated with Monroe County, Illinois, with a population of 2,707,648.
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Statewide data for Illinois
Population, race, income, age, and trends across Illinois
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.