16 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lancaster | 1 | 42,191 | 40,631 | 0.62% | 2,215 | 19 | City |
| Pickerington | 2 | 27,101 | 23,240 | 2.43% | 2,658 | 10 | City |
| South Bloomfield | 3 | 4,546 | 2,149 | 9.65% | 1,137 | 4 | Village |
| Lithopolis | 4 | 3,197 | 2,182 | 5.58% | 1,411 | 2 | Village |
| Baltimore | 5 | 3,112 | 3,042 | 0.39% | 1,318 | 2 | Village |
| Bremen | 6 | 1,534 | 1,492 | 0.46% | 1,782 | 1 | Village |
| Millersport | 7 | 1,000 | 979 | 0.4% | 1,075 | 1 | Village |
| Pleasantville | 8 | 959 | 944 | 0.31% | 3,539 | 0 | Village |
| Amanda | 9 | 684 | 666 | 0.44% | 2,158 | 0 | Village |
| Thurston | 10 | 611 | 608 | 0.16% | 1,512 | 0 | Village |
| Stoutsville | 11 | 580 | 580 | 0% | 502 | 1 | Village |
| Carroll | 12 | 500 | 502 | 0% | 795 | 1 | Village |
| Sugar Grove | 13 | 407 | 410 | 0% | 1,326 | 0 | Village |
| Rushville | 14 | 305 | 305 | 0% | 1,271 | 0 | Village |
| Darbyville | 15 | 190 | 186 | 0.53% | 368 | 1 | Village |
| West Rushville | 16 | 163 | 165 | 0% | 2,508 | 0 | Village |
Lancaster is the largest city in Fairfield County, with a population of 42,191.
West Rushville is the smallest city in Fairfield County, with a population of 163.
There are 16 cities in Fairfield County, Ohio.