| Name | Jefferson County |
| State | Kansas |
| FIPS Code | 20087 |
| County Seat | Oskaloosa |
| Timezone | Central Standard Time (CST) |
| Population (2022) | 19,036 |
| Population Growth Rate(2000-2022) | -3.96% |
| Majority Ethnicity | White 98.4% |
| Public School Majority Ethnicity | White 89% |
| Partisan Voting Index | Republican:+14 |
| Unemployment Rate (December 2024) | 3.1% |
| Area Code(s) | 785 / 913 |
| Race/Ethnicity | Percentage of Population (2022) |
|---|---|
| White | 98.4% |
| African American | 0.78% |
| Hispanic | 0.57% |
| Asian | 0.25% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 0% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 89.17% |
| African American | 0.63% |
| Hispanic | 4.78% |
| Asian | 0.16% |
| Native American | 0.6% |
| Hawaiin/Pacific Islander | 0.09% |