How many people live in Johnson County, IL?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 13,300 people living in Johnson County, IL. That makes Johnson County the 79th-most populous county in Illinois. It is home to 0.1% of people living in the state.
13.3K
population of Johnson County, IL (2024)
0.1%
County share of the Illinois population (2024)
About 13,300 people lived in Johnson County, IL in 2024.
Population estimates, 2000–2024
What are Johnson County, IL’s age demographics?
About 2,800 Johnson County residents are aged 65 and older in 2024. That represents 20.7% of its population. For comparison, the age group represents 17.9% of Illinois' population and 18% in the US overall.
Another 2,200 Johnson County residents, or 16.4% of the population, were children under 18. For comparison, the age group represents 21.2% of Illinois’ population and 21.6% in the US overall.
A lower share of Johnson County, IL's population is aged under 18 than the US as a whole.
Population estimates by age group, (2024)
What are Johnson County, IL’s racial and ethnic demographics?
Non-Hispanic white residents make up 80.9% of the Johnson County, IL population, higher than the national share of 57.5%.
In contrast, Johnson County’s Hispanic population accounts for 4.8%, below the 20% nationwide, and the non-Hispanic Asian population makes up 0.27% 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.
Johnson County, IL has a higher share of a non-Hispanic white population than Illinois as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Johnson County, IL is Vienna with about 1,400 residents in 2024.
Cities and towns in Johnson County, IL ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Vienna | 1,350 |
| 2. | Goreville | 1,054 |
| 3. | Cypress | 219 |
| 4. | Buncombe | 207 |
| 5. | New Burnside | 152 |
| 6. | Belknap | 86 |
| 7. | Simpson | 44 |
| 8. | Balance of Johnson County | 10,208 |
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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.
