Clay County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 80th-largest in Illinois
The population of Clay County, Illinois is 13,173 as of the 2023 American Community Survey, making it the 80th-largest county in Illinois. The median household income is $57,266, the median home value is $94,300, and the median age is 41.5.
The population of Clay County has declined 7.2% since 2010 (13,822 → 12,821), a -0.54% annualized rate.
13,173
Population
-0.54%
Annual growth
28
People / sq mi
$57,266
Median Income
$94,300
Median Home Value
Clay County covers 468 sq mi of land at 28.1 people per square mile.
About Clay County, IL
Clay County is a county in Illinois with a population of 13,173. It ranks #80 among counties in Illinois by population. The median age is 41.5, older than the national median. The population is 50.1% male and 49.9% female.
The median household income in Clay County is $57,266, below the US median of $74,580. 10.9% of residents live below the federal poverty level. Home values sit at a median of $94,300, with monthly rent averaging $709. The homeownership rate of 80.7% is higher than the national rate of 64.8%.
Educational attainment in Clay County reflects 15.6% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 6.2% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 26.1 minutes each way.
Clay County Population History (2010-2024)
The county of Clay County had a population of 13,822 in 2010 and 12,821 in 2024, a -7.2% growth over 14 years. The peak was 13,822 in 2010. Average annual growth rate: -0.53%.
12,821
Population (2024)
13,822
Population (2010)
13,822
Peak (2010)
-0.53%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 13,822 |
| 2011 | 13,721 |
| 2012 | 13,710 |
| 2013 | 13,550 |
| 2014 | 13,441 |
| 2015 | 13,395 |
| 2016 | 13,309 |
| 2017 | 13,259 |
| 2018 | 13,260 |
| 2019 | 13,177 |
| 2020 | 13,273 |
| 2021 | 13,166 |
| 2022 | 13,053 |
| 2023 | 12,945 |
| 2024 | 12,821 |
Race & Ethnicity
| White | 95.4% |
| Black or African American | 0.7% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.0% |
| Two or More Races | 0.0% |
Age & Sex
41.5
Median Age
49.9%
Female
50.1%
Male
20.7%
Age 65+
Age Distribution
Children (under 15): 18.6% · Seniors (65+): 20.7%
Income & Poverty
| Median household income | $57,266$-24,436 vs state |
| Mean household income | $79,425 |
| Per-capita income | $33,212 |
| Poverty rate | 10.9%+2.7% vs state |
| Unemployment rate | 3.3% |
| Employment-to-population | 53.3% |
Top Industries by Employment
The largest employment sector in Clay County is manufacturing, accounting for 24.4% of workers.
How residents commute
0.3%
Drive alone
0.8%
Carpool
85.5%
Public transit
6.2%
Work from home
26.1 min
Avg commute
Housing
$94,300$-156,200 vs state
Median home value
$709
Median rent
80.7%
Homeownership rate
6,147
Total housing units
88.4%
Occupied
11.6%
Vacant
19.3%
Renter-occupied
Social & access
94.4%
With health insurance
90.9%
With broadband internet
12.4%
Foreign-born
8.1%
Veterans (18+)
18.6%
With a disability
98.9%
Speak language other than English at home
Education
87.7%
High School+
15.6%
Bachelor's+
Largest cities in Illinois
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County rankings
Frequently Asked Questions
Clay County, Illinois has a population of 13,173 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 80th-largest county in Illinois. Population density is 28 people per square mile.
The population of Clay County has declined 7.2% since 2010 (13,822 → 12,821), a -0.54% annualized rate.
The median household income in Clay County, Illinois is $57,266, with mean (average) household income of $79,425 and per-capita income of $33,212. 10.9% of residents live below the federal poverty level.
In Clay County, the largest racial and ethnic groups are White (95.4%), Hispanic or Latino (2.0%), Black or African American (0.7%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Clay County, Illinois is 41.5 years. Residents are 49.9% female and 50.1% male.
The median home value in Clay County is $94,300 and median monthly rent is $709. 80.7% of occupied housing units are owner-occupied. The county has 6,147 total housing units, 11.6% of which are vacant.
The largest employment sector in Clay County, Illinois is manufacturing, employing 24.4% of workers. The unemployment rate is 3.3%.
Chicago is among the largest cities associated with Clay 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.