St. Clair County's 2026 population is estimated at 160,364, reflecting a 0.02% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). St. Clair County is the 14th largest county in Michigan. The 2010 population was 162,688 and has grown -1.43% since 2010.
Data after 2023 is projected based on recent change
Overall: 44.5 years
Female: 45.5 years
Male: 43.4 years
There are 127,743 adults, (32,649 of whom are seniors) in St. Clair County.
Female: 79,977 (49.9%)
Male: 80,244 (50.1%)
The racial composition of St. Clair County includes 91.21% White, and smaller percentages for Black or African American, other race, Asian, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 146,136 | 91.21% |
| Two or more races | 7,697 | 4.8% |
| Black or African American | 3,491 | 2.18% |
| Other race | 1,746 | 1.09% |
| Asian | 865 | 0.54% |
| Native American | 271 | 0.17% |
| Native Hawaiian or Pacific Islander | 15 | 0.01% |
St. Clair County 's average per capita income is $47,476. Household income levels show a median of $71,270. The poverty rate stands at 11.28%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $100,098 | $118,635 |
| Families | $87,930 | $105,549 |
| Households | $71,270 | $90,649 |
| Non Families | $41,280 | $56,878 |
Average Income
Median Household Income
Poverty Rate