How many people live in St. Louis County, MO?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 992,900 people living in St. Louis County, MO. That makes St. Louis County the most populous county in Missouri. It is home to 15.8% of people living in the state.
993K
population of St. Louis County, MO (2024)
15.8%
County share of the Missouri population (2024)
About 992,900 people lived in St. Louis County, MO in 2024.
Population estimates, 2000–2024
What are St. Louis County, MO’s age demographics?
About 199,300 St. Louis County, MO residents are aged 65 and older in 2024. That represents 20.1% of its population. For comparison, the age group represents 18.8% of Missouri’s population and 18% in the US overall.
Another 214,400 St. Louis County residents, or 21.6% of the population, were children under 18. For comparison, the age group represents 22% of Missouri’s population and 21.6% in the US overall.
A higher share of St. Louis County, MO's population is aged 65 or older than the US as a whole.
Population estimates by age group, (2024)
What are St. Louis County, MO’s racial and ethnic demographics?
Non-Hispanic white residents make up 62.9% of the St. Louis County, MO population, higher than the national share of 57.5%. St. Louis County, MO also has a larger share of people identifying as non-Hispanic Black or African American (25%) than the US overall (12.6%).
In contrast, St. Louis County’s Hispanic population accounts for 4.1%, below the 20% nationwide, and the non-Hispanic Asian population makes up 5.4% of the county, compared with 6.5% nationally.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.
St. Louis County, MO has a higher share of a non-Hispanic Black or African American population than Missouri as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in St. Louis County, MO is Florissant with about 51,300 residents in 2024.
Cities and towns in St. Louis County, MO ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Florissant | 51,290 |
| 2. | Chesterfield | 49,465 |
| 3. | Wildwood | 35,082 |
| 4. | University City | 34,349 |
| 5. | Ballwin | 31,036 |
| 6. | Kirkwood | 29,348 |
| 7. | Maryland Heights | 27,671 |
| 8. | Hazelwood | 24,951 |
| 9. | Webster Groves | 23,525 |
| 10. | Creve Coeur | 18,533 |
Keep exploring
Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
