DeKalb County, Illinois Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
DeKalb 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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B
Health Around averageAmong the top 5 healthiest counties in Illinois
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C
Income Below average
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C
Education Below averageBetter educated than 85% of counties in Illinois
Source: Map AI Methodology
Population: density and quick facts
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Population | 100,702 | 12,692,444 | 337,468,954 |
| Population density (per sq mi) | 158.7 | 219.1 | 86.4 |
| Population growth (%/yr) | -0.45% | -0.16% | 0.59% |
| Median age | 30.4 | 37.4 | 37.3 |
| Households | 39,550 | 5,035,584 | 130,235,071 |
Population in DeKalb County declined by 3.4% from 2009 to 2024, reaching 100,702 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in DeKalb County is Gen Z, aged 13–28, at 31.5% of residents. That is 10.2 points above Illinois as a whole.
- Gen Z 13–28 31,717 31.5% +10.2 pts
- Millennials 29–44 19,651 19.5% -2.4 pts
- Gen X 45–60 17,404 17.3% -3.1 pts
- Boomers 61–79 13,465 13.4% -3.5 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 50.2% of the people living in DeKalb County and men 49.8%.
- Women 50.2% Illinois 50.6%
- Men 49.8% Illinois 49.4%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in DeKalb County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
DeKalb County has a the economy index of C, which means it is somewhat prosperous.
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median household income | $71,059 | $84,042 | $80,455 |
| Income growth (%/yr) | 3.00% | 4.46% | 4.80% |
| Unemployment rate | 6.8% | 5.8% | 5.2% |
The median household income in DeKalb County is about 15% lower than in Illinois.
Housing
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median home price | $334,212 | $149,936 | $248,835 |
| Median rent | $1,048 | $1,274 | $1,407 |
| Homeownership rate | 61.4% | 67.1% | 65.2% |
The median home price in DeKalb County is about 26.6 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $1,048 per month for that long.
Commute Time & Mobility
Commuters in DeKalb County spend about 42 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 175 hours, about 7.3 full days, spent commuting.
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 21.0 | 23.6 | 22.4 |
| Round-trip commute (min) | 42.0 | 47.3 | 44.8 |
| Yearly time spent (hours) | 175 | 197 | 187 |
| Estimated yearly cost | $5,421 | $6,104 | $5,790 |
| Work from home | 9.3% | 15.9% | 15.0% |
| Highway traffic (vehicles/day) | 9,565 | 7,977 | 8,813 |
| Local road traffic (vehicles/day) | 1,116 | 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 DeKalb County is 21 minutes, shorter 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
DeKalb County has a education index of C, which means it is somewhat educated.
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 28.7% | 34.1% | 31.6% |
| Average household size | 2.42 | 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
DeKalb County has a health index of B, which means it is quite healthy.
| Metric | DeKalb County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 80.2 | 77.9 | 78.3 |
| Self-rated poor health | 12.5% | 15.6% | 16.3% |
| Smokers | 16.7% | 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).
DeKalb County, IL Compared With Nearby Counties
DeKalb County, IL is the 4th largest of the 6 counties compared here, 100,702 residents against a local median of 137,674. DeKalb County, IL's median home price, at $334,212, runs 55% above the $215,928 typical of the counties around it.
Median household income tells the same story from another angle: $71,059 against a local median of $103,524, 31% below it. The one measure here that carries a verdict is median household income, and at 31% below the local median it puts DeKalb County, IL at the weaker end of the local range. The counties themselves spread $286,130 on median home price, so DeKalb County, IL sits at one end of an already wide local range rather than apart from it. DeKalb County, IL has the highest median home price of the 6 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| DeKalb County, IL | 100,702 | $71,059 #5/6 | $334,212 #1/6 | 21.0 min #2/6 |
| Kane County, IL | 517,214 | $103,524 | $215,928 | 23.8 min |
| Boone County, IL | 53,226 | $85,291 | $66,484 | 23.3 min |
| Kendall County, IL | 137,674 | $110,609 | $332,795 | 30.6 min |
| McHenry County, IL | 312,591 | $105,514 | $263,961 | 26.8 min |
| Lee County, IL | 33,849 | $70,910 | $46,666 | 17.9 min |
Frequently Asked Questions
Common questions about DeKalb County, Illinois.
What is the population of DeKalb County, Illinois?
About 100,702 people live in DeKalb County, Illinois, in 39,550 households of 2.4 people on average. The median age is 30.4, so residents are younger than the U.S. median of 37.3 by about 7 years.
Is DeKalb County, Illinois urban or rural?
Averaged over its land area, DeKalb County, Illinois has 159 people per square mile, a density typical of a mix of suburbs, small towns and farmland. That is about 1.8 times the U.S. average of 86.
How affordable is housing in DeKalb County, Illinois?
The median home costs 4.7 times the median household income ($334,212 against $71,059), compared with 3.1 times nationally. A ratio of about 3 is traditionally considered affordable. Median rent of $1,048 a month takes about 18% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
Is unemployment high in DeKalb County, Illinois?
Unemployment in DeKalb County, Illinois is 6.8%, well above the U.S. rate of 5.2%, so job seekers may face more competition than elsewhere.
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