Clinton County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 37th-largest in Illinois
The population of Clinton County, Illinois is 36,899 as of the 2023 American Community Survey, making it the 37th-largest county in Illinois. The median household income is $82,314, the median home value is $180,500, and the median age is 41.4.
The population of Clinton County has declined 2.0% since 2010 (37,833 → 37,087), a -0.14% annualized rate.
36,899
Population
-0.14%
Annual growth
78
People / sq mi
$82,314
Median Income
$180,500
Median Home Value
Clinton County covers 474 sq mi of land at 77.9 people per square mile.
About Clinton County, IL
What sets Clinton County apart is money: median household income runs $82,314, near the US median of $78,538. Clinton County is a county in Illinois with a population of 36,899. It ranks #37 among counties in Illinois by population.
Households take in a median $82,314, comfortably near the US median of $78,538. The poverty rate, 5.7%, is on the lower side for US counties and below the national 12.4%. The typical home is valued at $180,500, with typical rent around $934.
Roughly 24.4% of adults have a bachelor’s, below the national 35.0%. Remote work is on the higher side at 11.1%, below the national 14.0%, and the average commute runs about 26 minutes each way.
Taken together, the income and housing figures place Clinton County firmly in the higher-cost, higher-earning tier of US counties — a profile that tends to track dense job markets and competitive housing.
Clinton County Population History (2010-2024)
The county of Clinton County had a population of 37,833 in 2010 and 37,087 in 2024, a -2.0% growth over 14 years. The peak was 38,024 in 2011. Average annual growth rate: -0.14%.
37,087
Population (2024)
37,833
Population (2010)
38,024
Peak (2011)
-0.14%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 37,833 |
| 2011 | 38,024 |
| 2012 | 37,908 |
| 2013 | 37,725 |
| 2014 | 37,637 |
| 2015 | 37,657 |
| 2016 | 37,594 |
| 2017 | 37,649 |
| 2018 | 37,666 |
| 2019 | 37,440 |
| 2020 | 36,913 |
| 2021 | 36,898 |
| 2022 | 36,987 |
| 2023 | 36,886 |
| 2024 | 37,087 |
Race & Ethnicity
| White | 91.4% |
| Black or African American | 3.2% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.1% |
| Two or More Races | 0.0% |
Age & Sex
41.4
Median Age
48.2%
Female
51.8%
Male
18.2%
Age 65+
Age Distribution
Children (under 15): 17.7% · Seniors (65+): 18.2%
Income & Poverty
| Median household income | $82,314+$612 vs state |
| Mean household income | $104,928 |
| Per-capita income | $41,334 |
| Poverty rate | 5.7%-2.5% vs state |
| Unemployment rate | 2.0% |
| Employment-to-population | 60.3% |
Top Industries by Employment
The largest employment sector in Clinton County is professional & business services, accounting for 24.7% of workers.
How residents commute
0.5%
Drive alone
2.4%
Carpool
79.1%
Public transit
11.1%
Work from home
25.7 min
Avg commute
Housing
$180,500$-70,000 vs state
Median home value
$934
Median rent
79.3%
Homeownership rate
15,677
Total housing units
92.3%
Occupied
7.7%
Vacant
20.7%
Renter-occupied
Social & access
95.1%
With health insurance
92.8%
With broadband internet
17.0%
Foreign-born
8.9%
Veterans (18+)
13.6%
With a disability
95.9%
Speak language other than English at home
Education
92.0%
High School+
24.4%
Bachelor's+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
County rankings
Frequently Asked Questions
Clinton County, Illinois has a population of 36,899 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 37th-largest county in Illinois. Population density is 78 people per square mile.
The population of Clinton County has declined 2.0% since 2010 (37,833 → 37,087), a -0.14% annualized rate.
The median household income in Clinton County, Illinois is $82,314, with mean (average) household income of $104,928 and per-capita income of $41,334. 5.7% of residents live below the federal poverty level.
In Clinton County, the largest racial and ethnic groups are White (91.4%), Black or African American (3.2%), Hispanic or Latino (1.1%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Clinton County, Illinois is 41.4 years. Residents are 48.2% female and 51.8% male.
The median home value in Clinton County is $180,500 and median monthly rent is $934. 79.3% of occupied housing units are owner-occupied. The county has 15,677 total housing units, 7.7% of which are vacant.
The largest employment sector in Clinton County, Illinois is professional, scientific, and management services, employing 24.7% of workers. The unemployment rate is 2.0%.
Chicago is among the largest cities associated with Clinton County, Illinois, with a population of 2,707,648.
Clinton County, IL Climate
Clinton County, IL has an average annual temperature of 12.5°C (55°F) and receives about 986 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
12.5°C
Avg Temp
986
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -2° / 28° | 49 mm |
| February | 1° / 33° | 59 mm |
| March | 7° / 44° | 95 mm |
| April | 13° / 55° | 94 mm |
| May | 18° / 64° | 105 mm |
| June | 23° / 74° | 97 mm |
| July | 26° / 78° | 91 mm |
| August | 24° / 76° | 74 mm |
| September | 20° / 69° | 80 mm |
| October | 14° / 57° | 74 mm |
| November | 7° / 45° | 87 mm |
| December | 1° / 34° | 81 mm |
1970–2000 normals from WorldClim 2.1 (~9 km grid). Precipitation can be less precise near mountains or coastlines, where rainfall varies sharply over short distances.
Best time to visit Clinton County, IL
The most comfortable months to visit Clinton County, IL are typically September, June and August, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 31°C high). The coldest is January (near -7°C low). May is usually the wettest month.
Where to stay near Clinton County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.