How many people live in Union County, OH?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 71,700 people living in Union County, OH. That makes Union County the 36th-most populous county in Ohio. It is home to 0.6% of people living in the state.
71.7K
population of Union County, OH (2024)
0.6%
County share of the Ohio population (2024)
About 71,700 people lived in Union County, OH in 2024.
Population estimates, 2000–2024
What are Union County, OH’s age demographics?
About 10,000 Union County, OH residents are aged 65 and older in 2024. That represents 13.9% of its population. For comparison, the age group represents 19.1% of Ohio’s population and 18% in the US overall.
Another 17,000 Union County residents, or 23.8% of the population, were children under 18. For comparison, the age group represents 21.7% of Ohio’s population and 21.6% in the US overall.
A lower share of Union County, OH's population is aged 65 or older than the US as a whole.
Population estimates by age group, (2024)
What are Union County, OH’s racial and ethnic demographics?
Non-Hispanic white residents make up 83.4% of the Union County, OH population, higher than the national share of 57.5%. Union County, OH also has a larger share of people identifying as non-Hispanic Asian (7.4%) than the US overall (6.5%).
In contrast, Union County’s Hispanic population accounts for 4.3%, below the 20% nationwide, and the non-Hispanic Black or African American population makes up 3% 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.
Union County, OH has a higher share of a non-Hispanic white population than Ohio as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Union County, OH is Marysville with about 29,300 residents in 2024.
Cities and towns in Union County, OH ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Marysville (pt.) | 29,276 |
| 2. | Dublin (pt.) | 4,361 |
| 3. | Allen | 2,791 |
| 4. | Richwood | 2,575 |
| 5. | Liberty | 2,409 |
| 6. | Taylor | 1,801 |
| 7. | York | 1,544 |
| 8. | Millcreek | 1,532 |
| 9. | Jackson | 1,122 |
| 10. | Washington | 932 |
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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.
