St. Charles County's 2026 population is estimated at 435,262, reflecting a 1.34% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). St. Charles County is the 3rd largest county in Missouri. The 2010 population was 361,808 and has grown 20.3% since 2010.
Data after 2023 is projected based on recent change
Overall: 39.8 years
Female: 40.8 years
Male: 38.8 years
There are 321,155 adults, (70,408 of whom are seniors) in St. Charles County.
Female: 209,458 (50.5%)
Male: 205,077 (49.5%)
The racial composition of St. Charles County includes 84.03% White, 5.15% Black or African American, 3.05% Asian, and smaller percentages for other race, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 348,354 | 84.03% |
| Two or more races | 26,513 | 6.4% |
| Black or African American | 21,335 | 5.15% |
| Asian | 12,632 | 3.05% |
| Other race | 5,181 | 1.25% |
| Native American | 333 | 0.08% |
| Native Hawaiian or Pacific Islander | 187 | 0.05% |
St. Charles County 's average per capita income is $62,951. Household income levels show a median of $104,692. The poverty rate stands at 5.2%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $139,375 | $163,152 |
| Families | $126,505 | $149,775 |
| Households | $104,692 | $129,305 |
| Non Families | $57,044 | $77,440 |
Average Income
Median Household Income
Poverty Rate