Johnson County, Illinois Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 79th-largest in Illinois
The population of Johnson County, Illinois is 13,350 as of the 2023 American Community Survey, making it the 79th-largest county in Illinois. The median household income is $65,203, the median home value is $148,200, and the median age is 42.7.
The population of Johnson County has grown 5.7% since 2010 (12,598 → 13,320), a +0.40% annualized rate.
13,350
Population
+0.40%
Annual growth
39
People / sq mi
$65,203
Median Income
$148,200
Median Home Value
Johnson County covers 344 sq mi of land at 38.8 people per square mile.
About Johnson County, IL
Johnson County is a county in Illinois with a population of 13,350. It ranks #79 among counties in Illinois by population. The median age is 42.7, older than the national median. The population is 57.0% male and 43.0% female.
The median household income in Johnson County is $65,203, below the US median of $74,580. 13.1% of residents live below the federal poverty level. Home values sit at a median of $148,200, with monthly rent averaging $634. The homeownership rate of 84.7% is higher than the national rate of 64.8%.
Educational attainment in Johnson County reflects 18.8% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 5.5% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 27.1 minutes each way.
Johnson County Population History (2010-2024)
The county of Johnson County had a population of 12,598 in 2010 and 13,320 in 2024, a 5.7% growth over 14 years. The peak was 13,481 in 2021. Average annual growth rate: 0.42%.
13,320
Population (2024)
12,598
Population (2010)
13,481
Peak (2021)
0.42%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 12,598 |
| 2011 | 12,849 |
| 2012 | 12,851 |
| 2013 | 12,861 |
| 2014 | 12,882 |
| 2015 | 12,768 |
| 2016 | 12,445 |
| 2017 | 12,394 |
| 2018 | 12,380 |
| 2019 | 12,380 |
| 2020 | 13,322 |
| 2021 | 13,481 |
| 2022 | 13,401 |
| 2023 | 13,355 |
| 2024 | 13,320 |
Race & Ethnicity
| White | 82.2% |
| Black or African American | 7.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 4.8% |
| Two or More Races | 0.0% |
Age & Sex
42.7
Median Age
43.0%
Female
57.0%
Male
20.4%
Age 65+
Age Distribution
Children (under 15): 14.7% · Seniors (65+): 20.4%
Income & Poverty
| Median household income | $65,203$-16,499 vs state |
| Mean household income | $77,971 |
| Per-capita income | $28,028 |
| Poverty rate | 13.1%+4.9% vs state |
| Unemployment rate | 1.0% |
| Employment-to-population | 40.7% |
Top Industries by Employment
The largest employment sector in Johnson County is professional & business services, accounting for 31.6% of workers.
How residents commute
0.0%
Drive alone
0.3%
Carpool
86.1%
Public transit
5.5%
Work from home
27.1 min
Avg commute
Housing
$148,200$-102,300 vs state
Median home value
$634
Median rent
84.7%
Homeownership rate
5,538
Total housing units
74.6%
Occupied
25.4%
Vacant
15.3%
Renter-occupied
Social & access
92.1%
With health insurance
86.8%
With broadband internet
26.1%
Foreign-born
7.7%
Veterans (18+)
18.1%
With a disability
96.9%
Speak language other than English at home
Education
85.9%
High School+
18.8%
Bachelor's+
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County rankings
Frequently Asked Questions
Johnson County, Illinois has a population of 13,350 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 79th-largest county in Illinois. Population density is 39 people per square mile.
The population of Johnson County has grown 5.7% since 2010 (12,598 → 13,320), a +0.40% annualized rate.
The median household income in Johnson County, Illinois is $65,203, with mean (average) household income of $77,971 and per-capita income of $28,028. 13.1% of residents live below the federal poverty level.
In Johnson County, the largest racial and ethnic groups are White (82.2%), Black or African American (7.6%), Hispanic or Latino (4.8%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Johnson County, Illinois is 42.7 years. Residents are 43.0% female and 57.0% male.
The median home value in Johnson County is $148,200 and median monthly rent is $634. 84.7% of occupied housing units are owner-occupied. The county has 5,538 total housing units, 25.4% of which are vacant.
The largest employment sector in Johnson County, Illinois is professional, scientific, and management services, employing 31.6% of workers. The unemployment rate is 1.0%.
Chicago is among the largest cities associated with Johnson 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.