Johnson County's 2026 population is estimated at 645,940, reflecting a 1.07% growth rate over the past year (World Population Review estimate based on U.S. Census Bureau data). Johnson County is the largest county in Kansas. The 2010 population was 545,681 and has grown 18.37% since 2010.
Data after 2023 is projected based on recent change
Overall: 38.6 years
Female: 39.4 years
Male: 37.7 years
There are 474,880 adults, (99,005 of whom are seniors) in Johnson County.
Female: 313,839 (50.6%)
Male: 306,792 (49.4%)
The racial composition of Johnson County includes 78.52% White, 5.22% Asian, 4.95% Black or African American, and smaller percentages for other race, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
| Race | Population ↓ | Percentage (of total) |
|---|---|---|
| White | 487,296 | 78.52% |
| Two or more races | 54,315 | 8.75% |
| Asian | 32,405 | 5.22% |
| Black or African American | 30,711 | 4.95% |
| Other race | 13,790 | 2.22% |
| Native American | 1,940 | 0.31% |
| Native Hawaiian or Pacific Islander | 174 | 0.03% |
Johnson County 's average per capita income is $67,570. Household income levels show a median of $109,208. The poverty rate stands at 5.41%.
| Name | Median ↓ | Mean |
|---|---|---|
| Married Families | $153,255 | $192,616 |
| Families | $136,798 | $176,517 |
| Households | $109,208 | $146,136 |
| Non Families | $62,249 | $82,943 |
Average Income
Median Household Income
Poverty Rate
