Population
250,708
2025
−2.5% since 2020
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. Resident population, July 1 estimate.
St. Clair County, IL: population growth, jobs and income
St. Clair County lost 667 residents between 2024 and 2025 (−0.3%).
St. Clair County had an estimated 250,708 residents in 2025, down 2.5% (6,349 fewer people) since 2020. That is slower than Illinois as a whole (−0.6%), and the 64th fastest growth of 102 counties in Illinois.
Data as of 2025 · updated
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In the St. Clair County report
One-time $99 PDF: everything on this page for St. Clair County, ranked against Illinois and the U.S., plus these figures that are not on the free page:
- Median gross rent$1,090/mo2020–24
- Vacant homes, incl. seasonal and second homes12.8%2020–24
- New homes permitted, last 12 months4142025-10/2026-09
- Rent growth, 5 yearsIn the report
- Permits in 5+ unit buildingsIn the report
- IRS income moving in (net AGI)In the report
- Neighbouring-county comparison tableIn the report
What's inside: 5 pages
- 1 Summary, headline numbers and ranks (free preview)
- 2 Ranks and the neighbouring-county table
- 3 Migration, with IRS mover and income flows
- 4 Rent, vacant homes, permits and employers
- 5 Every source and the methods
Headline numbers
Net domestic migration
−393
2025
−1.6 per 1,000 residents
−6,029 in total, 2021–2025
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. People moving in from other U.S. counties minus people moving out.
Unemployment rate
4.5%
2025
+0.1 pts since 2019
Source: U.S. Bureau of Labor Statistics, Local Area Unemployment Statistics, 2025. Annual average unemployment rate.
New homes permitted
463
2025
−14.6% since 2021
1.8 per 1,000 residents
Source: U.S. Census Bureau, Building Permits Survey, 2025. Housing units authorized by building permits in the year.
Median household income
$73,854
2020–24
+28.5% since 2016–20
Source: U.S. Census Bureau, American Community Survey 5-year estimates, 2020–24. American Community Survey 5-year estimate.
Private-sector employment
72,871
2023
−3.7% since 2018
Source: U.S. Census Bureau, County Business Patterns, 2023. Paid employees of private employers in mid-March (County Business Patterns).
What the numbers say
Net domestic migration was negative in 2025: 393 more people moved out to other U.S. counties than moved in.
Private employers had 72,871 paid employees in mid-March 2023, −3.7% since 2018 (County Business Patterns).
Unemployment averaged 4.5% in 2025, 0.1 points higher than in 2019 (before the pandemic).
Builders were authorized to start 463 new homes in 2025, or 1.8 per 1,000 residents.
Median household income was $73,854 in the 2020–24 American Community Survey, +28.5% since 2016–20.
Across the 3,107 U.S. counties with a comparable estimate, its population growth ranks 2,574th.
Part of the St. Louis, MO-IL metro area.
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St. Clair County population by year
| Year | Population | Change |
|---|---|---|
| 2025 | 250,708 | −667 |
| 2024 | 251,375 | −857 |
| 2023 | 252,232 | −598 |
| 2022 | 252,830 | −2,364 |
| 2021 | 255,194 | −1,863 |
| 2020 | 257,057 | – |
Census Bureau population estimates, July 1 of each year.
What drove the change in St. Clair County
St. Clair County lost 6,349 people since 2020; the biggest drag was domestic migration (−6,029).
| Component | 2025 | 2020–25 | Share |
|---|---|---|---|
| Natural changebirths minus deaths | −501 | −1,791 | |
| International migrationfrom and to other countries | +210 | +1,462 | |
| Domestic migrationfrom and to other U.S. counties | −393 | −6,029 | |
| Census adjustmentbalancing residual | +17 | +9 | |
| Total change | −667 | −6,349 |
Census Bureau population estimates, components of change, each year July 1 to June 30. The components add up to the change in the estimate; the Census adjustment is the small balancing figure the Bureau publishes.
How it ranks
| Measure | In Illinois | Among U.S. counties |
|---|---|---|
| Population growth | 64th of 102 | 2,574th of 3,107 |
| Net domestic migration per 1,000 residents | 62nd of 102 | 2,162nd of 3,108 |
| Private-sector job growth | 66th of 102 | 2,341st of 3,092 |
| Median household income | 29th of 102 | 919th of 3,107 |
| Lowest unemployment rate | 48th of 102 | 2,094th of 3,108 |
| New homes permitted per 1,000 residents | 17th of 98 | 1,607th of 3,005 |
1st = highest (lowest for unemployment). Counties are ranked only against others with a figure for the same period.
Get the county report — $99
The County Growth and Demographics Report for St. Clair County, IL as a PDF, from federal data: population and migration, housing and rents, permits, private employers and jobs, unemployment, ranks in the state and the country, and neighbouring counties, with a source next to every number. Pay once, no subscription.
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Neighbouring counties
Over 2020–25, St. Clair County's population change (−2.5%) was ahead of 1 of its 7 neighbouring counties and behind 6.
5 of its 7 neighbouring counties had a higher median household income than St. Clair County's $73,854 (2020–24).
| County | Population2025 | Population change2020–25 | Net domestic migration per 1,000 residents2025 | Homes permitted per 1,000 residents2025 | Median household income2020–24 |
|---|---|---|---|---|---|
| St. Clair County, IL This county | 250,708 | −2.5% | −1.6 | 1.8 | $73,854 |
| Monroe County, IL | 34,840 | −0.3% | −2.5 | 1.9 | $102,880 |
| St. Louis, MO | 278,144 | −7.4% | −13.5 | 1.0 | $56,160 |
| Madison County, IL | 263,110 | −1.0% | 1.2 | 1.7 | $75,793 |
| Randolph County, IL | 29,921 | −0.6% | 3.1 | 0.2 | $68,131 |
| Washington County, IL | 13,564 | −1.2% | 0.0 | 1.1 | $78,224 |
| Clinton County, IL | 37,128 | +0.6% | 1.0 | 1.4 | $86,588 |
| St. Louis County, MO | 990,911 | −1.2% | −3.4 | 1.0 | $82,936 |
Census Bureau population estimates and building permits, American Community Survey 5-year income. Rates per 1,000 residents. – means no figure, or a base too small for a change or rate (it would swing on a few people). A figure from another period shows its year and is left out of the comparison.
Questions
Is St. Clair County growing?
No. Its population fell 2.5% between 2020 and 2025, about 6,349 fewer people (Census Bureau population estimates). Illinois as a whole changed −0.6% over the same years. That ranks 64th of 102 counties in Illinois for population growth.
How many people moved to St. Clair County?
On net, none in 2025: about 393 more people moved out to other U.S. counties than moved in (Census Bureau net domestic migration estimate).
What is the unemployment rate in St. Clair County?
It averaged 4.5% in 2025 (BLS Local Area Unemployment Statistics, annual average).
What is the population of St. Clair County?
About 250,708 people, according to the U.S. Census Bureau's population estimate for July 1, 2025.
How many jobs are in St. Clair County?
Private employers there had 72,871 paid employees in mid-March 2023, −3.7% since 2018 (Census Bureau County Business Patterns; government jobs and the self-employed are not counted).
What Beacon CRE covers in Illinois
Map, parcel and listing layers cover North and South Carolina only for now. This page and the other Illinois county pages carry the public federal growth figures.
St. Clair County data alerts
Email me when St. Clair County gets new Census numbers: population, building permits, jobs and income. About 4 emails a year, one click to stop.
Sources and method
- U.S. Census Bureau, Population Estimates Program (Vintage 2025)
- U.S. Bureau of Labor Statistics, Local Area Unemployment Statistics
- U.S. Census Bureau, Building Permits Survey
- U.S. Census Bureau, American Community Survey 5-year estimates
- U.S. Census Bureau, County Business Patterns
Each number shows its own period. Changes compare the latest period with five years earlier (or the earliest period available). Beacon CRE last refreshed these figures on 2026-11-05. Figures come from public federal statistics and are informational only, not investment advice. Check the source before relying on a number. Methodology: how we compute every number. More on every layer: data sources and licences.
Jobs outside North and South Carolina use County Business Patterns (paid private-sector employees in mid-March); wages and government jobs are not included.