St. Clair County, Michigan
Located in Michigan, St. Clair County has a population of 160,221 residents and a median age of 44.5 years, making it the #434 most populous county out of 3,222 nationwide. In terms of economic indicators, the county has a poverty rate of 11.3%. The median home value is $224,600, and the median household income is $71,270, which is 5% below the national median.
Demographics
St. Clair County has a population of 160,221, making it the #434 most populous county in the US. The median age is 44.5 years, which is 14.4% above the national median.
Population Trend
Rankings →Year-over-Year Population Growth
Age & Sex Distribution
Race & Ethnicity
Nativity
Geographic Mobility (Past Year)
Economy
The median household income in St. Clair County is $71,270, ranking #1,110 out of 3,222 counties — 5.2% below the national median. The poverty rate is 11.3% and unemployment stands at 5.7%.
Median Household Income Trend
Rankings →Income Distribution
Industry of Employment
Occupation
Housing
The median home value in St. Clair County is $224,600 (-20.3% vs national). Renters pay a median of $1,029/mo and the homeownership rate is 80.8%.
Median Home Value Trend
Rankings →Household Type
Education
In St. Clair County, 20.3% of adults age 25+ hold a bachelor's degree or higher, which is 39.7% below the national average, ranking #1,947 out of 3,222 counties.
Bachelor's Degree or Higher Trend
Rankings →Health & Wellbeing
Life expectancy in St. Clair County is 75.0 years. 16.2% of adults report poor or fair health and 4.8% lack health insurance. Data from County Health Rankings (2025).
Life Expectancy Trend
Substance Use
16.0% of adults in St. Clair County smoke , 40.8% are obese , and 23.4% report excessive drinking. The drug overdose death rate is 34.2 per 100,000.
Adult Smoking Trend
Safety
The homicide rate in St. Clair County is 1.6 per 100,000 and the suicide rate is 20.8 per 100,000. Motor vehicle deaths occur at a rate of 12.5 per 100,000.
Homicide Rate Trend
Families & Children
14.3% of children in St. Clair County live in poverty and the infant mortality rate is 6.4 per 1,000 live births. The teen birth rate is 13.7 per 1,000 females age 15–19.
Infant Mortality Trend
Civic & Transportation
Voter turnout in St. Clair County is 73.9%. The mean commute time is 31.4 min, which is 13.9% above the national average.
Voter Turnout Trend
Mean Commute Time Trend
Rankings →Elections
In the 2024 presidential election, St. Clair County voted Republican with a margin of 34.6%. The vote was 32% Dem / 66.6% Rep. Compared to 2020, the margin shifted 4.4 toward Republicans .
Vote Share Over Time
About St. Clair County, Michigan
St. Clair County, Michigan has a total population of 160,221, making it the 434th most populous county in the United States. The median age in St. Clair County is 44.5 years, which is 14.4% above the national median of 38.9 years.
The median household income in St. Clair County is $71,270, which ranks #1,110 of 3,222 counties nationwide. This is 5.2% below the national median of $75,149. The poverty rate is 11.3%, lower than the national rate of 12.6%. The unemployment rate stands at 5.7%.
The median home value in St. Clair County is $224,600, 20.3% below the national median. Renters in St. Clair County pay a median gross rent of $1,029 per month. The homeownership rate is 80.8%, compared to the national rate of 64.4%.
In St. Clair County, 20.3% of residents aged 25 and older hold a bachelor's degree or higher, 39.7% below the national average of 33.7%. Health insurance coverage stands at 95.1% of the population. The average commute time for workers is 31.4 min.
St. Clair County is a diverse community. The largest racial or ethnic group is White (non-Hispanic) at 89.7% of the population, followed by Hispanic or Latino (3.7%) and Two or More Races (3.6%).
All data for St. Clair County, Michigan comes from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates. These figures are estimates based on survey sampling and are subject to margin of error. For the most detailed and up-to-date data, visit the Census Bureau's official data portal.