How many people live in Washington County, MO?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 23,600 people living in Washington County, MO. That makes Washington County the 47th-most populous county in Missouri. It is home to 0.38% of people living in the state.
23.6K
population of Washington County, MO (2024)
0.38%
County share of the Missouri population (2024)
About 23,600 people lived in Washington County, MO in 2024.
Population estimates, 2000–2024
What are Washington County, MO’s age demographics?
About 4,400 Washington County residents are aged 65 and older in 2024. That represents 18.8% of its population. For comparison, the age group represents 18.8% of Missouri’s population and 18% in the US overall.
Another 5,300 Washington County, MO residents, or 22.6% 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 Washington County, MO's population is aged 45–64 than the US as a whole.
Population estimates by age group, (2024)
What are Washington County, MO’s racial and ethnic demographics?
Non-Hispanic white residents make up 93.5% of the Washington County, MO population, higher than the national share of 57.5%.
In contrast, Washington County’s Hispanic population accounts for 1.4%, below the 20% nationwide, and the non-Hispanic Black or African American population makes up 2.7% of the county, compared with 12.6% 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.
Washington County, MO has a higher share of a non-Hispanic white population than Missouri as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Washington County, MO is Potosi with about 2,500 residents in 2024.
Cities and towns in Washington County, MO ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Potosi | 2,549 |
| 2. | Irondale | 368 |
| 3. | Mineral Point | 234 |
| 4. | Caledonia | 132 |
| 5. | Balance of Washington County | 20,300 |
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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.
