Johnson County's 2026 population is estimated at 13,250, reflecting a -0.26% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Johnson County is the 78th largest county in Illinois. The 2010 population was 12,598 and has grown 5.18% since 2010.
Data after 2023 is projected based on recent change
Overall: 41.4 years
Female: 43.5 years
Male: 40.5 years
There are 10,893 adults, (2,630 of whom are seniors) in Johnson County.
Female: 5,706 (42.7%)
Male: 7,670 (57.3%)
The racial composition of Johnson County includes 80.53% White, 7.8% Black or African American, and smaller percentages for other race, Asian and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 10,772 | 80.53% |
| Two or more races | 1,399 | 10.46% |
| Black or African American | 1,043 | 7.8% |
| Other race | 129 | 0.96% |
| Asian | 33 | 0.25% |
Johnson County 's average per capita income is $45,304. Household income levels show a median of $62,528. The poverty rate stands at 17.58%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $89,563 | - |
| Families | $79,509 | $91,906 |
| Households | $62,528 | $78,647 |
| Non Families | $39,832 | $52,994 |
Average Income
Median Household Income
Poverty Rate
