Marion County, Illinois Demographics
Population trends, housing costs, income, commuting, and health, all on one page.
Marion 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 averageLess healthy than 89% of counties in Illinois
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C
Income Below averageLess wealthy than 72% of counties in Illinois
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D
Education Well below averageLess educated than 75% of counties in Illinois
Source: Map AI Methodology
Population: density and quick facts
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Population | 37,000 | 12,692,444 | 337,468,954 |
| Population density (per sq mi) | 64.2 | 219.1 | 86.4 |
| Population growth (%/yr) | -0.50% | -0.16% | 0.59% |
| Median age | 42.5 | 37.4 | 37.3 |
| Households | 15,512 | 5,035,584 | 130,235,071 |
Population in Marion County declined by 6.3% from 2009 to 2024, reaching 37,000 in 2024.
Population Growth 2009–2024
Race & Ethnicity
Age & Sex
The largest generation in Marion County is Gen X, aged 45–60, at 20.7% of residents. That is 0.3 points above Illinois as a whole.
- Gen Z 13–28 7,124 19.3% -2.0 pts
- Millennials 29–44 7,019 19.0% -2.9 pts
- Gen X 45–60 7,653 20.7% +0.3 pts
- Boomers 61–79 7,128 19.3% +2.4 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 50.9% of the people living in Marion County and men 49.1%.
- Women 50.9% Illinois 50.6%
- Men 49.1% Illinois 49.4%
How many residents match a customer profile?
Residents matching this profile
100% of everyone living in Marion County
Pick an age range and a women/men split and the figure above answers with how many residents that profile reaches.
Economy
Marion County has a the economy index of C, which means it is somewhat prosperous.
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median household income | $61,117 | $84,042 | $80,455 |
| Income growth (%/yr) | 4.34% | 4.46% | 4.80% |
| Unemployment rate | 5.9% | 5.8% | 5.2% |
The median household income in Marion County is about 27% lower than in Illinois.
Housing
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median home price | $27,338 | $149,936 | $248,835 |
| Median rent | $793 | $1,274 | $1,407 |
| Homeownership rate | 74.7% | 67.1% | 65.2% |
The median home price in Marion County is about 2.9 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $793 per month for that long.
Commute Time & Mobility
Commuters in Marion County spend about 33 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 139 hours, about 5.8 full days, spent commuting.
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 16.6 | 23.6 | 22.4 |
| Round-trip commute (min) | 33.3 | 47.3 | 44.8 |
| Yearly time spent (hours) | 139 | 197 | 187 |
| Estimated yearly cost | $4,298 | $6,104 | $5,790 |
| Work from home | 4.8% | 15.9% | 15.0% |
| Highway traffic (vehicles/day) | 3,953 | 7,977 | 8,813 |
| Local road traffic (vehicles/day) | 824 | 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 Marion County is 17 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
Marion County has a education index of D, which means it is barely educated.
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 15.4% | 34.1% | 31.6% |
| Average household size | 2.33 | 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
Marion County has a health index of C, which means it is somewhat healthy.
| Metric | Marion County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 75.6 | 77.9 | 78.3 |
| Self-rated poor health | 17.8% | 15.6% | 16.3% |
| Smokers | 21.7% | 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).
Marion County, IL Compared With Nearby Counties
Marion County, IL is typical in size for this group, 37,000 residents against a local median of 35,535, so the measures below are close to a like for like comparison. The measure that sets Marion County, IL apart most is median home price: $27,338, 81% below the local median of $142,355.
The counties themselves spread $177,742 on median home price, so Marion County, IL sits at one end of an already wide local range rather than apart from it. Marion County, IL has the 5th highest median home price of the 5 areas compared here.
| Area | Population | Median household income | Median home price | Commute |
|---|---|---|---|---|
| Marion County, IL | 37,000 | $61,117 #4/5 | $27,338 #5/5 | 16.6 min #2/5 |
| Jefferson County, IL | 36,549 | $62,660 | $225,000 | 16.7 min |
| Fayette County, IL | 21,314 | $60,976 | $47,257 | 21.8 min |
| Clinton County, IL | 36,954 | $86,530 | $64,999 | 21.8 min |
| Effingham County, IL | 34,520 | $81,070 | $219,711 | 13.8 min |
Frequently Asked Questions
Common questions about Marion County, Illinois.
How big is Marion County, Illinois by population?
About 37,000 people live in Marion County, Illinois, in 15,512 households of 2.3 people on average. The median age is 42.5, so residents are older than the U.S. median of 37.3 by about 5 years.
Is Marion County, Illinois urban or rural?
Averaged over its land area, Marion County, Illinois has 64 people per square mile, a density typical of rural areas. That is close to the U.S. average of 86.
Is Marion County, Illinois an affordable place to live?
The median home costs 0.4 times the median household income ($27,338 against $61,117), compared with 3.1 times nationally. That is within the traditional rule of thumb of about 3 times income. Median rent of $793 a month takes about 16% of the median household's income, below the 30% level at which HUD considers renters cost-burdened.
How common is a college degree in Marion County, Illinois?
15.4% of adults in Marion 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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