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
Homeownership is the standout figure in Johnson County: 84.7% of homes are owner-occupied, higher than the national rate. Johnson County is a county in Illinois with a population of 13,350.
Household earnings are middling, with a median of $65,203 — below the US median of $78,538. The poverty rate is 13.1%, above the national 12.4%. Homes carry a median value of $148,200, with typical rent around $634.
Roughly 18.8% 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 27 minutes each way.
The ownership rate anchors the housing story in Johnson County, and tends to move with the age structure and home-value figures above.
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+
Largest cities in Illinois
Other counties in Illinois
Part of Illinois
Metro areas in Illinois
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.
Johnson County, IL Climate
Johnson County, IL has an average annual temperature of 13.5°C (56°F) and receives about 1199 mm of precipitation per year. The warmest month is July and the coldest is January. Figures are 1970–2000 climate normals.
13.5°C
Avg Temp
1199
Precip (mm/yr)
Jul
Hottest Month
Jan
Coldest Month
| Month | Avg (°C/°F) | Precip |
|---|---|---|
| January | 0° / 31° | 79 mm |
| February | 2° / 36° | 87 mm |
| March | 8° / 47° | 122 mm |
| April | 14° / 56° | 117 mm |
| May | 19° / 65° | 125 mm |
| June | 23° / 74° | 104 mm |
| July | 26° / 78° | 97 mm |
| August | 25° / 76° | 90 mm |
| September | 21° / 70° | 85 mm |
| October | 15° / 58° | 78 mm |
| November | 8° / 47° | 108 mm |
| December | 3° / 37° | 107 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 Johnson County, IL
The most comfortable months to visit Johnson County, IL are typically September, June and August, when temperatures are mildest and rainfall is relatively low. The hottest month is July (around 32°C high). The coldest is January (near -5°C low). May is usually the wettest month.
Where to stay near Johnson County
Visiting or relocating to Johnson County, IL? Compare hotels and short-term rentals across the county — live availability and prices.
Top-rated places to stay near Johnson County
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a move to Johnson County?
Get relocation and cost-of-living insights for Johnson County, IL by email. No spam, unsubscribe anytime.
More from Illinois
Population 5,185,812
Population 927,263
Population 711,885
Population 698,450
Full rankings of Illinois counties
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.