| Name | Jefferson County |
| State | Iowa |
| FIPS Code | 19101 |
| County Seat | Fairfield |
| Timezone | Central Standard Time (CST) |
| Population (2022) | 16,791 |
| Population Growth Rate(2000-2022) | -7.01% |
| Majority Ethnicity | White 88.15% |
| Public School Majority Ethnicity | White 85% |
| Partisan Voting Index | Republican:+2 |
| Unemployment Rate (November 2024) | 2.6% |
| Area Code(s) | 641 / 319 |
| Race/Ethnicity | Percentage of Population (2022) |
|---|---|
| White | 88.15% |
| African American | 4.96% |
| Hispanic | 0.81% |
| Asian | 6.07% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 0% |
| Race/Ethnicity | Percentage of Public School Students (2023) |
|---|---|
| White | 84.63% |
| African American | 1.3% |
| Hispanic | 6.13% |
| Asian | 3.11% |
| Native American | 0.23% |
| Hawaiin/Pacific Islander | 0.09% |