St. Clair County's 2026 population is estimated at 10,058, reflecting a 1.05% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). St. Clair County is the 85th largest county in Missouri. The 2010 population was 9,823 and has grown 2.39% since 2010.
Data after 2023 is projected based on recent change
Overall: 46.1 years
Female: 46 years
Male: 46.3 years
There are 7,549 adults, (2,457 of whom are seniors) in St. Clair County.
Female: 4,687 (48.9%)
Male: 4,900 (51.1%)
The racial composition of St. Clair County includes 93.46% White, and smaller percentages for Black or African American, other race, Asian, Native American and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 8,960 | 93.46% |
| Two or more races | 439 | 4.58% |
| Black or African American | 77 | 0.8% |
| Other race | 71 | 0.74% |
| Asian | 24 | 0.25% |
| Native American | 16 | 0.17% |
St. Clair County 's average per capita income is $40,914. Household income levels show a median of $53,043. The poverty rate stands at 14.68%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $74,601 | - |
| Families | $69,120 | $84,894 |
| Households | $53,043 | $69,413 |
| Non Families | $31,647 | $40,044 |
Average Income
Median Household Income
Poverty Rate
