Knox County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 29th-largest in Illinois
The population of Knox County, Illinois is 49,294 as of the 2023 American Community Survey, making it the 29th-largest county in Illinois. The median household income is $53,291, the median home value is $104,900, and the median age is 42.4.
The population of Knox County has declined 7.9% since 2010 (52,911 → 48,716), a -0.59% annualized rate.
49,294
Population
-0.59%
Annual growth
69
People / sq mi
$53,291
Median Income
$104,900
Median Home Value
Knox County covers 716 sq mi of land at 68.8 people per square mile.
About Knox County, IL
Knox County is a county in Illinois with a population of 49,294. It ranks #29 among counties in Illinois by population. The median age is 42.4, older than the national median. The population is 51.1% male and 48.9% female.
The median household income in Knox County is $53,291, below the US median of $74,580. 10.5% of residents live below the federal poverty level. Home values sit at a median of $104,900, with monthly rent averaging $725. The homeownership rate of 69.8% is higher than the national rate of 64.8%.
Educational attainment in Knox County reflects 20.3% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 5.7% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 20.6 minutes each way.
Knox County Population History (2010-2024)
The county of Knox County had a population of 52,911 in 2010 and 48,716 in 2024, a -7.9% growth over 14 years. The peak was 52,911 in 2010. Average annual growth rate: -0.59%.
48,716
Population (2024)
52,911
Population (2010)
52,911
Peak (2010)
-0.59%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 52,911 |
| 2011 | 52,702 |
| 2012 | 52,302 |
| 2013 | 52,130 |
| 2014 | 51,945 |
| 2015 | 51,377 |
| 2016 | 50,931 |
| 2017 | 50,601 |
| 2018 | 50,008 |
| 2019 | 49,669 |
| 2020 | 49,806 |
| 2021 | 49,333 |
| 2022 | 48,713 |
| 2023 | 48,663 |
| 2024 | 48,716 |
Race & Ethnicity
| White | 83.3% |
| Black or African American | 7.8% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.7% |
| Two or More Races | 0.0% |
Age & Sex
42.4
Median Age
48.9%
Female
51.1%
Male
22.2%
Age 65+
Age Distribution
Children (under 15): 16.6% · Seniors (65+): 22.2%
Income & Poverty
| Median household income | $53,291$-28,411 vs state |
| Mean household income | $69,635 |
| Per-capita income | $29,614 |
| Poverty rate | 10.5%+2.3% vs state |
| Unemployment rate | 2.4% |
| Employment-to-population | 51.3% |
Top Industries by Employment
The largest employment sector in Knox County is professional & business services, accounting for 31.7% of workers.
How residents commute
0.5%
Drive alone
3.6%
Carpool
80.5%
Public transit
5.7%
Work from home
20.6 min
Avg commute
Housing
$104,900$-145,600 vs state
Median home value
$725
Median rent
69.8%
Homeownership rate
23,788
Total housing units
87.3%
Occupied
12.7%
Vacant
30.2%
Renter-occupied
Social & access
94.5%
With health insurance
87.9%
With broadband internet
16.3%
Foreign-born
7.1%
Veterans (18+)
14.7%
With a disability
94.1%
Speak language other than English at home
Education
89.3%
High School+
20.3%
Bachelor's+
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County rankings
Frequently Asked Questions
Knox County, Illinois has a population of 49,294 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 29th-largest county in Illinois. Population density is 69 people per square mile.
The population of Knox County has declined 7.9% since 2010 (52,911 → 48,716), a -0.59% annualized rate.
The median household income in Knox County, Illinois is $53,291, with mean (average) household income of $69,635 and per-capita income of $29,614. 10.5% of residents live below the federal poverty level.
In Knox County, the largest racial and ethnic groups are White (83.3%), Black or African American (7.8%), Hispanic or Latino (0.7%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Knox County, Illinois is 42.4 years. Residents are 48.9% female and 51.1% male.
The median home value in Knox County is $104,900 and median monthly rent is $725. 69.8% of occupied housing units are owner-occupied. The county has 23,788 total housing units, 12.7% of which are vacant.
The largest employment sector in Knox County, Illinois is professional, scientific, and management services, employing 31.7% of workers. The unemployment rate is 2.4%.
Chicago is among the largest cities associated with Knox County, Illinois, with a population of 2,707,648.
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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.