8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fairfield | 1 | 9,200 | 9,449 | -0.54% | 1,391 | 6.61 | City |
| Batavia | 2 | 418 | 433 | -0.71% | 679 | 0.62 | City |
| Maharishi Vedic City | 3 | 312 | 272 | 2.63% | 93 | 3.34 | City |
| Libertyville | 4 | 267 | 277 | -0.74% | 528 | 0.51 | City |
| Lockridge | 5 | 238 | 243 | -0.42% | 381 | 0.62 | City |
| Packwood | 6 | 177 | 184 | -0.56% | 236 | 0.75 | City |
| Pleasant Plain | 7 | 78 | 82 | -1.27% | 77 | 1.01 | City |
| Coppock | 8 | 35 | 37 | 0% | 152 | 0.23 | City |
Fairfield is the largest city in Jefferson County, with a population of 9,200.
Coppock is the smallest city in Jefferson County.
There are 8 cities in Jefferson County, Iowa.