St. Clair County, Missouri Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 89th-largest in Missouri
The population of St. Clair County, Missouri is 9,451 as of the 2023 American Community Survey, making it the 89th-largest county in Missouri. The median household income is $46,731, the median home value is $142,500, and the median age is 47.2.
The population of St. Clair County has grown 0.3% since 2010 (9,823 → 9,848), a +0.02% annualized rate.
9,451
Population
+0.02%
Annual growth
14
People / sq mi
$46,731
Median Income
$142,500
Median Home Value
St. Clair County covers 675 sq mi of land at 14.0 people per square mile.
About St. Clair County, MO
St. Clair County is a county in Missouri with a population of 9,451. It ranks #89 among counties in Missouri by population. The median age is 47.2, older than the national median. The population is 50.8% male and 49.2% female.
The median household income in St. Clair County is $46,731, below the US median of $74,580. 12.8% of residents live below the federal poverty level. Home values sit at a median of $142,500, with monthly rent averaging $607. The homeownership rate of 75.7% is higher than the national rate of 64.8%.
Educational attainment in St. Clair County reflects 13.7% of adults 25 and older holding a bachelor's degree or higher, below the national average of 34.3%. Roughly 6.6% of workers primarily work from home, below the national work-from-home rate of 14.2%. The average commute is 28.8 minutes each way.
St. Clair County Population History (2010-2024)
The county of St. Clair County had a population of 9,823 in 2010 and 9,848 in 2024, a 0.3% growth over 14 years. The peak was 9,848 in 2024. Average annual growth rate: 0.02%.
9,848
Population (2024)
9,823
Population (2010)
9,848
Peak (2024)
0.02%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 9,823 |
| 2011 | 9,694 |
| 2012 | 9,533 |
| 2013 | 9,499 |
| 2014 | 9,446 |
| 2015 | 9,427 |
| 2016 | 9,310 |
| 2017 | 9,395 |
| 2018 | 9,431 |
| 2019 | 9,450 |
| 2020 | 9,346 |
| 2021 | 9,416 |
| 2022 | 9,581 |
| 2023 | 9,743 |
| 2024 | 9,848 |
Race & Ethnicity
| White | 93.6% |
| Black or African American | 0.8% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 2.1% |
| Two or More Races | 0.0% |
Age & Sex
47.2
Median Age
49.2%
Female
50.8%
Male
25.8%
Age 65+
Age Distribution
Children (under 15): 17.1% · Seniors (65+): 25.8%
Income & Poverty
| Median household income | $46,731$-22,189 vs state |
| Mean household income | $60,329 |
| Per-capita income | $26,548 |
| Poverty rate | 12.8%+4.4% vs state |
| Unemployment rate | 1.2% |
| Employment-to-population | 49.3% |
Top Industries by Employment
The largest employment sector in St. Clair County is professional & business services, accounting for 21.5% of workers.
How residents commute
0.1%
Drive alone
2.8%
Carpool
76.5%
Public transit
6.6%
Work from home
28.8 min
Avg commute
Housing
$142,500$-73,100 vs state
Median home value
$607
Median rent
75.7%
Homeownership rate
5,295
Total housing units
77.2%
Occupied
22.8%
Vacant
24.3%
Renter-occupied
Social & access
87.3%
With health insurance
89.5%
With broadband internet
29.4%
Foreign-born
9.3%
Veterans (18+)
22.8%
With a disability
98.5%
Speak language other than English at home
Education
87.9%
High School+
13.7%
Bachelor's+
Largest cities in Missouri
Other counties in Missouri
Part of Missouri
Metro areas in Missouri
County rankings
Frequently Asked Questions
St. Clair County, Missouri has a population of 9,451 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 89th-largest county in Missouri. Population density is 14 people per square mile.
The population of St. Clair County has grown 0.3% since 2010 (9,823 → 9,848), a +0.02% annualized rate.
The median household income in St. Clair County, Missouri is $46,731, with mean (average) household income of $60,329 and per-capita income of $26,548. 12.8% of residents live below the federal poverty level.
In St. Clair County, the largest racial and ethnic groups are White (93.6%), Hispanic or Latino (2.1%), Black or African American (0.8%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in St. Clair County, Missouri is 47.2 years. Residents are 49.2% female and 50.8% male.
The median home value in St. Clair County is $142,500 and median monthly rent is $607. 75.7% of occupied housing units are owner-occupied. The county has 5,295 total housing units, 22.8% of which are vacant.
The largest employment sector in St. Clair County, Missouri is professional, scientific, and management services, employing 21.5% of workers. The unemployment rate is 1.2%.
Kansas City is among the largest cities associated with St. Clair County, Missouri, with a population of 508,233.
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Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.