St. Charles County, Missouri Demographics 2026
St. Charles County, Missouri has a population of 414,535, the 3rd most populous county in Missouri. The median household income is $104,692 and the median home value is $320,800. The poverty rate is 5.2%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
St. Charles County Quick Facts
How St. Charles County Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 409,830 | 414,535 | +1.1% |
| Median household income | $102,912 | $104,692 | +1.7% |
| Median home value | $296,800 | $320,800 | +8.1% |
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
A less diverse community where one racial or ethnic group represents a large majority.
State average: 40 | National average: 61
Education
Educational Attainment (Adults 25+)
Cities & Places in St. Charles County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| O'Fallon | 93,801 | $110,443 | 5.4% | $326,200 |
| St. Charles | 71,508 | $85,937 | 7.3% | $298,700 |
| St. Peters | 59,092 | $91,637 | 5.7% | $269,900 |
| Wentzville | 47,061 | $112,394 | 5.4% | $331,300 |
| Lake St. Louis | 18,066 | $125,693 | 4.3% | $405,900 |
| Dardenne Prairie | 13,503 | $152,500 | 1.3% | $432,000 |
| Cottleville | 5,937 | $131,310 | 2.0% | $435,400 |
| Weldon Spring | 5,310 | $158,548 | 0.7% | $544,300 |
| St. Paul | 3,456 | $159,022 | 0.5% | $443,600 |
| Foristell | 1,096 | $116,581 | 1.7% | $431,700 |
| Josephville | 664 | $107,708 | 18.1% | $494,600 |
| Flint Hill | 583 | $130,208 | 3.1% | $475,500 |
| West Alton | 467 | $111,500 | 1.7% | $153,100 |
| New Melle | 452 | $114,375 | 4.4% | $397,800 |
| Portage Des Sioux | 340 | $62,188 | 12.7% | $173,000 |
| Augusta | 285 | $103,750 | 2.1% | $362,500 |
| Weldon Spring Heights | 121 | $143,750 | 1.7% | $447,500 |
| Defiance | 63 | N/A | 0.0% | $512,500 |
Explore Missouri Rankings
Population Overview
St. Charles County is located in Missouri with a total population of 414,535. It is the 3rd most populous county out of 115 in Missouri. The county encompasses 18 Census-designated places.
Age Demographics
The median age in St. Charles County is 39.8 years. This is 2% higher than the state median of 39.0 years.
Economy, Income & Housing
The median household income in St. Charles County is $104,692. This is 48% higher than the state median of $70,702. It is also 30% higher than the national median of $80,734. The poverty rate stands at 5.2%. This is 59% lower than the state poverty rate of 12.6%. The unemployment rate is 2.9%. This is 27% lower than the state rate of 4.0%. The median home value is $320,800. Housing costs are 39% higher than the state median of $230,300. The home-value-to-income ratio is 3.1x. 80.5% of occupied housing units are owner-occupied. This homeownership rate is 18% higher than the state average of 68.1%.
Race & Ethnicity
The largest racial or ethnic group in St. Charles County is White (non-Hispanic), making up 83.0% of the population. Black or African American residents account for 5.0%. The Black or African American population (5.0%) is well below the state average of 10.9%.
Education
42.7% of residents aged 25 and older hold a bachelor's degree or higher. This places St. Charles County in the top 10% of all counties in the state for educational attainment. This is 32% higher than the state rate of 32.4%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 95.7%. Notably, 15.8% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All figures for St. Charles County come from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates, with comparisons drawn against Missouri and national averages from the same dataset. See our methodology page for how each metric is defined, or data.census.gov for official tables with margins of error.
Frequently Asked Questions
What is the population of St. Charles County, Missouri?
St. Charles County has a population of 414,535, making it the 3rd most populous county in Missouri.
What is the median income in St. Charles County?
The median household income in St. Charles County is $104,692 with a poverty rate of 5.2%.
How many cities are in St. Charles County, Missouri?
St. Charles County contains 18 Census-designated places.