Johnson County, Illinois Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Johnson County, IL Population Density Map and Area Scores
Area Score
Health, income and education, each graded from F to A+. Explore interactive maps for deeper analysis.
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C
Health Below averageAmong the 5 least healthy counties in Illinois
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D
Income Well below averageAmong the 5 least wealthy counties in Illinois
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F
Education Well below averageLess educated than 89% of counties in Illinois
Source: Map AI Methodology
Population: density and quick facts
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Population | 13,376 | 12,692,444 | 337,468,954 |
| Population density (per sq mi) | 38.4 | 219.1 | 86.4 |
| Population growth (%/yr) | 0.52% | -0.16% | 0.59% |
| Median age | 42.1 | 37.4 | 37.3 |
| Households | 4,099 | 5,035,584 | 130,235,071 |
Population in Johnson County declined by 2.0% from 2009 to 2024, reaching 13,376 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Johnson County is Millennials, aged 29–44, at 21.4% of residents. That is 0.5 points below Illinois as a whole.
- Gen Z 13–28 2,787 20.8% -0.4 pts
- Millennials 29–44 2,860 21.4% -0.5 pts
- Gen X 45–60 2,777 20.8% +0.4 pts
- Boomers 61–79 2,653 19.8% +2.9 pts
Residents by birth cohort, from the 2025 age distribution. The right-hand figure is how far each cohort's share sits above or below Illinois, in percentage points. Children younger than Gen Z and the generations before the Boomers are counted in the population but not shown here, so these shares do not add up to 100%.
Male and female share
Women are 42.5% of the people living in Johnson County and men 57.5%.
- Women 42.5% Illinois 50.6%
- Men 57.5% Illinois 49.4%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Johnson County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Johnson County has a the economy index of D, which means it is barely prosperous.
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median household income | $63,615 | $84,042 | $80,455 |
| Income growth (%/yr) | 4.75% | 4.46% | 4.80% |
| Unemployment rate | 3.5% | 5.8% | 5.2% |
The median household income in Johnson County is about 24% lower than in Illinois.
Housing
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median home price | $42,069 | $149,936 | $248,835 |
| Median rent | $780 | $1,274 | $1,407 |
| Homeownership rate | 82.0% | 67.1% | 65.2% |
The median home price in Johnson County is about 4.5 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $780 per month for that long.
Commute Time & Mobility
Commuters in Johnson County spend about 60 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 250 hours, about 10.4 full days, spent commuting.
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 30.0 | 23.6 | 22.4 |
| Round-trip commute (min) | 60.0 | 47.3 | 44.8 |
| Yearly time spent (hours) | 250 | 197 | 187 |
| Estimated yearly cost | $7,754 | $6,104 | $5,790 |
| Work from home | 4.8% | 15.9% | 15.0% |
| Highway traffic (vehicles/day) | 3,263 | 7,977 | 8,813 |
| Local road traffic (vehicles/day) | 490 | 1,547 | 1,355 |
Fastest commutes among counties in
Illinois:
Edgar County (12.0 min), Brown County (12.7 min), Morgan County (13.1 min).
Slowest:
Calhoun County (43.8 min), Pulaski County (31.2 min), Pope County (31.0 min).
The average commute time in Johnson County is 30 minutes, longer than the 24 minutes in Illinois.
Estimated yearly cost applies a single national wage rule of thumb (U.S. Bureau of Labor Statistics average hourly earnings), not a measurement of wages in this area. Traffic volume figures come from proprietary Ticon and TrafficZoom data.
Education & Households
Johnson County has a education index of F, which means it scores poorly in education.
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 15.4% | 34.1% | 31.6% |
| Average household size | 2.82 | 2.46 | 2.53 |
Highest education index among counties in
Illinois:
DuPage County (0.4), Champaign County (0.4), Lake County (0.4).
Lowest:
Hardin County (0.2), Fayette County (0.2), Perry County (0.2).
Health
Johnson County has a health index of C, which means it is somewhat healthy.
| Metric | Johnson County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 77.4 | 77.9 | 78.3 |
| Self-rated poor health | 22.5% | 15.6% | 16.3% |
| Smokers | 26.2% | 19.2% | 19.0% |
Highest health index among counties in
Illinois:
DuPage County (0.8), Champaign County (0.8), Monroe County (0.8).
Lowest:
Alexander County (0.8), Pulaski County (0.8), Gallatin County (0.8).
Johnson County, IL Compared With Nearby Counties
How Johnson County, IL compares with the 1 counties closest to it.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Johnson County, IL | 13,376 | $63,615 #2/2 | $42,069 #2/2 | 30.0 min #2/2 |
| Williamson County, IL | 66,874 | $65,527 | $94,999 | 18.5 min |
Frequently Asked Questions
Common questions about Johnson County, Illinois.
How big is Johnson County, Illinois by population?
About 13,376 people live in Johnson County, Illinois, in 4,099 households of 2.8 people on average. The median age is 42.1, so residents are older than the U.S. median of 37.3 by about 5 years.
How densely populated is Johnson County, Illinois?
Averaged over its land area, Johnson County, Illinois has 38 people per square mile, a density typical of rural areas. That is about 44% of the U.S. average of 86.
How affordable is housing in Johnson County, Illinois?
The median home costs 0.7 times the median household income ($42,069 against $63,615), compared with 3.1 times nationally. That is within the traditional rule of thumb of about 3 times income. Median rent of $780 a month takes about 15% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
Is it hard to find a job in Johnson County, Illinois?
Unemployment in Johnson County, Illinois is only 3.5%, well below the U.S. rate of 5.2%, a sign of a tight labor market where employers compete for workers.
How common is a college degree in Johnson County, Illinois?
15.4% of adults in Johnson County, Illinois hold a bachelor's degree or higher (about 1 in 6), well below the U.S. share of 31.6%.
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