Warren County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 65th-largest in Illinois
The population of Warren County, Illinois is 16,576 as of the 2023 American Community Survey, making it the 65th-largest county in Illinois. The median household income is $64,650, the median home value is $101,300, and the median age is 38.7.
The population of Warren County has declined 8.4% since 2010 (17,710 → 16,217), a -0.63% annualized rate.
16,576
Population
-0.63%
Annual growth
31
People / sq mi
$64,650
Median Income
$101,300
Median Home Value
Warren County covers 542 sq mi of land at 30.6 people per square mile.
About Warren County, IL
In Warren County, home values do the distinguishing — a median of $101,300. Warren County is a county in Illinois with a population of 16,576.
The typical household here earns about $64,650, below the US median of $78,538. About 7.5% of residents live below the federal poverty level, below the national 12.4%. Real estate is inexpensive, with a typical home worth only $101,300, with typical rent around $694.
Roughly 22.0% of adults have a bachelor’s, below the national 35.0%. Most workers commute: only 5.5% work from home, below the national 14.0%, and the average commute runs about 19 minutes each way.
Warren County Population History (2010-2024)
The county of Warren County had a population of 17,710 in 2010 and 16,217 in 2024, a -8.4% growth over 14 years. The peak was 17,831 in 2011. Average annual growth rate: -0.63%.
16,217
Population (2024)
17,710
Population (2010)
17,831
Peak (2011)
-0.63%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 17,710 |
| 2011 | 17,831 |
| 2012 | 17,742 |
| 2013 | 17,660 |
| 2014 | 17,705 |
| 2015 | 17,448 |
| 2016 | 17,283 |
| 2017 | 17,133 |
| 2018 | 16,979 |
| 2019 | 16,816 |
| 2020 | 16,832 |
| 2021 | 16,595 |
| 2022 | 16,368 |
| 2023 | 16,224 |
| 2024 | 16,217 |
Race & Ethnicity
| White | 84.9% |
| Black or African American | 2.8% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.9% |
| Two or More Races | 0.0% |
Age & Sex
38.7
Median Age
49.9%
Female
50.1%
Male
19.6%
Age 65+
Age Distribution
Children (under 15): 18.6% · Seniors (65+): 19.6%
Income & Poverty
| Median household income | $64,650$-17,052 vs state |
| Mean household income | $82,733 |
| Per-capita income | $33,620 |
| Poverty rate | 7.5%-0.7% vs state |
| Unemployment rate | 3.2% |
| Employment-to-population | 59.1% |
Top Industries by Employment
The largest employment sector in Warren County is professional & business services, accounting for 28.9% of workers.
How residents commute
0.4%
Drive alone
4.0%
Carpool
82.3%
Public transit
5.5%
Work from home
19.4 min
Avg commute
Housing
$101,300$-149,200 vs state
Median home value
$694
Median rent
78.1%
Homeownership rate
7,598
Total housing units
88.5%
Occupied
11.5%
Vacant
21.9%
Renter-occupied
Social & access
94.0%
With health insurance
92.4%
With broadband internet
21.0%
Foreign-born
6.4%
Veterans (18+)
13.7%
With a disability
88.8%
Speak language other than English at home
Education
86.6%
High School+
22.0%
Bachelor's+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
County rankings
Frequently Asked Questions
Warren County, Illinois has a population of 16,576 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 65th-largest county in Illinois. Population density is 31 people per square mile.
The population of Warren County has declined 8.4% since 2010 (17,710 → 16,217), a -0.63% annualized rate.
The median household income in Warren County, Illinois is $64,650, with mean (average) household income of $82,733 and per-capita income of $33,620. 7.5% of residents live below the federal poverty level.
In Warren County, the largest racial and ethnic groups are White (84.9%), Black or African American (2.8%), Hispanic or Latino (1.9%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Warren County, Illinois is 38.7 years. Residents are 49.9% female and 50.1% male.
The median home value in Warren County is $101,300 and median monthly rent is $694. 78.1% of occupied housing units are owner-occupied. The county has 7,598 total housing units, 11.5% of which are vacant.
The largest employment sector in Warren County, Illinois is professional, scientific, and management services, employing 28.9% of workers. The unemployment rate is 3.2%.
Chicago is among the largest cities associated with Warren County, Illinois, with a population of 2,707,648.
Warren County, IL Climate
Warren County, IL has an average annual temperature of 10.2°C (50°F) and receives about 959 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
10.2°C
Avg Temp
959
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | -6° / 22° | 38 mm |
| February | -3° / 27° | 37 mm |
| March | 4° / 39° | 71 mm |
| April | 11° / 51° | 96 mm |
| May | 17° / 62° | 106 mm |
| June | 22° / 71° | 106 mm |
| July | 24° / 75° | 111 mm |
| August | 23° / 73° | 99 mm |
| September | 18° / 65° | 97 mm |
| October | 12° / 53° | 75 mm |
| November | 4° / 39° | 67 mm |
| December | -3° / 27° | 56 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 Warren County, IL
The most comfortable months to visit Warren County, IL are typically June, August and September, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 30°C high). The coldest is January (near -10°C low). July is usually the wettest month.
Where to stay near Warren County
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.