St. Charles County, Missouri Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 3rd-largest in Missouri
The population of St. Charles County, Missouri is 409,830 as of the 2023 American Community Survey, making it the 3rd-largest county in Missouri. The median household income is $102,912, the median home value is $296,800, and the median age is 39.6.
The population of St. Charles County has grown 17.1% since 2010 (361,808 → 423,726), a +1.13% annualized rate.
409,830
Population
+1.13%
Annual growth
731
People / sq mi
$102,912
Median Income
$296,800
Median Home Value
St. Charles County covers 561 sq mi of land at 731.2 people per square mile.
About St. Charles County, MO
St. Charles County is a county in Missouri with a population of 409,830. It ranks #3 among counties in Missouri by population. The median age is 39.6, in line with the national median. The population is 49.4% male and 50.6% female.
The median household income in St. Charles County is $102,912, above the US median of $74,580. 3.0% of residents live below the federal poverty level. Home values sit at a median of $296,800, with monthly rent averaging $1,312. The homeownership rate of 80.7% is higher than the national rate of 64.8%.
Educational attainment in St. Charles County reflects 42.4% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 16.0% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 24.9 minutes each way.
St. Charles County Population History (2010-2024)
The county of St. Charles County had a population of 361,808 in 2010 and 423,726 in 2024, a 17.1% growth over 14 years. The peak was 423,726 in 2024. Average annual growth rate: 1.14%.
423,726
Population (2024)
361,808
Population (2010)
423,726
Peak (2024)
1.14%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 361,808 |
| 2011 | 365,614 |
| 2012 | 369,175 |
| 2013 | 374,378 |
| 2014 | 379,956 |
| 2015 | 385,108 |
| 2016 | 390,724 |
| 2017 | 395,153 |
| 2018 | 398,656 |
| 2019 | 401,625 |
| 2020 | 406,423 |
| 2021 | 410,515 |
| 2022 | 414,055 |
| 2023 | 417,958 |
| 2024 | 423,726 |
Race & Ethnicity
| White | 85.0% |
| Black or African American | 5.1% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 0.9% |
| Two or More Races | 0.0% |
Age & Sex
39.6
Median Age
50.6%
Female
49.4%
Male
16.4%
Age 65+
Age Distribution
Children (under 15): 18.6% · Seniors (65+): 16.4%
Income & Poverty
| Median household income | $102,912+$33,992 vs state |
| Mean household income | $127,112 |
| Per-capita income | $49,859 |
| Poverty rate | 3.0%-5.4% vs state |
| Unemployment rate | 2.0% |
| Employment-to-population | 67.3% |
Top Industries by Employment
The largest employment sector in St. Charles County is professional & business services, accounting for 21.6% of workers.
How residents commute
0.1%
Drive alone
0.7%
Carpool
76.2%
Public transit
16.0%
Work from home
24.9 min
Avg commute
Housing
$296,800+$81,200 vs state
Median home value
$1,312
Median rent
80.7%
Homeownership rate
164,594
Total housing units
96.4%
Occupied
3.6%
Vacant
19.3%
Renter-occupied
Social & access
95.7%
With health insurance
97.0%
With broadband internet
26.2%
Foreign-born
6.8%
Veterans (18+)
11.1%
With a disability
94.5%
Speak language other than English at home
Education
95.5%
High School+
42.4%
Bachelor's+
Largest cities in Missouri
Other counties in Missouri
Part of Missouri
Metro areas in Missouri
County rankings
Common questions about St. Charles County, MO
Frequently Asked Questions
St. Charles County, Missouri has a population of 409,830 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 3rd-largest county in Missouri. Population density is 731 people per square mile.
The population of St. Charles County has grown 17.1% since 2010 (361,808 → 423,726), a +1.13% annualized rate.
The median household income in St. Charles County, Missouri is $102,912, with mean (average) household income of $127,112 and per-capita income of $49,859. 3.0% of residents live below the federal poverty level.
In St. Charles County, the largest racial and ethnic groups are White (85.0%), Black or African American (5.1%), Hispanic or Latino (0.9%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in St. Charles County, Missouri is 39.6 years. Residents are 50.6% female and 49.4% male.
The median home value in St. Charles County is $296,800 and median monthly rent is $1,312. 80.7% of occupied housing units are owner-occupied. The county has 164,594 total housing units, 3.6% of which are vacant.
The largest employment sector in St. Charles County, Missouri is professional, scientific, and management services, employing 21.6% of workers. The unemployment rate is 2.0%.
Kansas City is among the largest cities associated with St. Charles County, Missouri, with a population of 508,233.
More from Missouri
Population 996,618
Population 717,021
Population 301,121
Population 293,109
Full rankings of Missouri counties
Statewide data for Missouri
Population, race, income, age, and trends across Missouri
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.