St. Clair County, IL Population Statistics: Density Map Data
Analyze local population trends, population density map, housing costs, and the local economy.
Area Snapshot Statistics
Key statistics on population, economy, housing, and commuting compared to state and national averages. Explore interactive maps for deeper analysis.
Population: density and quick facts
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Population | 253,307 | 12,497,595 | 334,821,731 |
| Population density (per sq mi) | 375.6 | 215.8 | 85.8 |
| Population growth (%/yr) | -0.62% | -0.18% | 0.57% |
| Median age | 38.1 | 37.3 | 37.1 |
| Households | 101,271 | 5,000,691 | 128,459,983 |
Population in St. Clair County declined by 2.7% from 2009 to 2023, reaching 254,773 in 2023.
Population Growth 2009–2023
Race & Ethnicity
Economy
St. Clair County has a the economy index of C, which means it is somewhat prosperous.
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median household income | $70,146 | $82,179 | $78,145 |
| Income growth (%/yr) | 5.00% | 4.78% | 5.07% |
| Unemployment rate | 5.5% | 5.8% | 5.2% |
The median household income in St. Clair County is about 15% lower than in Illinois.
Housing
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Median home price | $100,531 | $162,405 | $242,182 |
| Median rent | $1,032 | $1,226 | $1,342 |
| Homeownership rate | 67.8% | 66.8% | 65.1% |
The median home price in St. Clair County is about 8.1 years' worth of rent — buying at the median price costs roughly as much as paying the median rent of $1,032 per month for that long.
Commute Time & Mobility
Commuters in St. Clair County spend about 44 minutes on the road round trip each working day. Over a typical 250-day work year, that adds up to roughly 182 hours, about 7.6 full days, spent commuting.
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| One-way commute (min) | 21.8 | 23.8 | 22.5 |
| Round-trip commute (min) | 43.6 | 47.6 | 44.9 |
| Yearly time spent (hours) | 182 | 198 | 187 |
| Estimated yearly cost | $5,635 | $6,148 | $5,803 |
| Work from home | 10.9% | 14.0% | 13.4% |
| Highway traffic (vehicles/day) | 10,578 | 7,977 | 8,813 |
| Local road traffic (vehicles/day) | 1,794 | 1,547 | 1,355 |
Fastest commutes among counties in
Illinois:
Edgar County (12.1 min), Brown County (12.8 min), McDonough County (13.0 min).
Slowest:
Calhoun County (46.4 min), Cook County (30.8 min), Kendall County (30.7 min).
The average commute time in St. Clair County is 22 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
St. Clair County has a education index of C, which means it is somewhat educated.
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Bachelor's degree or higher | 28.2% | 34.1% | 31.6% |
| Average household size | 2.47 | 2.48 | 2.54 |
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
St. Clair County has a health index of C, which means it is somewhat healthy.
| Metric | St. Clair County | Illinois Avg | U.S. Average |
|---|---|---|---|
| Life expectancy (years) | 75.9 | 77.9 | 78.3 |
| Self-rated poor health | 18.2% | 15.6% | 16.3% |
| Smokers | 19.3% | 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).
Frequently Asked Questions
Common questions about St. Clair County, Illinois.
What is the population of St. Clair County, Illinois?
The population of St. Clair County, Illinois is 253,307, compared to the U.S. total of 334,821,731.
What is the population density of St. Clair County, Illinois?
The population density of St. Clair County, Illinois is 375.6 people per square mile, compared to the U.S. average of 85.8 people per square mile.
What is the median household income in St. Clair County, Illinois?
The median household income in St. Clair County, Illinois is $70,146, compared to the U.S. median of $78,145.
What is the median home price in St. Clair County, Illinois?
The median home price in St. Clair County, Illinois is $100,531, compared to the U.S. median of $242,182.
What is the unemployment rate in St. Clair County, Illinois?
The unemployment rate in St. Clair County, Illinois is 5.5%, compared to the U.S. average of 5.2%.