38 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Violet township | 1 | 51,643 | 46,014 | 2.45% | 1,241 | 41.60 | Township |
| Lancaster | 2 | 41,946 | 40,636 | 0.63% | 2,203 | 19.04 | City |
| Pickerington | 3 | 26,586 | 23,260 | 2.57% | 2,608 | 10.20 | City |
| Bloom township | 4 | 11,538 | 10,227 | 2.27% | 310 | 37.16 | Township |
| Blacklick Estates | 5 | 9,092 | 10,097 | 0.3% | 4,816 | 1.89 | CDP |
| Liberty township | 6 | 8,620 | 8,234 | 1.13% | 171 | 50.33 | Township |
| Walnut township | 7 | 6,916 | 6,688 | 0.96% | 144 | 48.06 | Township |
| Pleasant township | 8 | 6,472 | 6,197 | 1.28% | 187 | 34.63 | Township |
| Berne township | 9 | 5,197 | 5,089 | 0.78% | 118 | 43.96 | Township |
| Hocking township | 10 | 4,920 | 4,851 | 0.12% | 150 | 32.78 | Township |
| Rush Creek township | 11 | 4,156 | 3,977 | 1.12% | 112 | 37.18 | Township |
| Clearcreek township | 12 | 4,153 | 4,120 | 0.48% | 114 | 36.30 | Township |
| Lithopolis | 13 | 3,060 | 2,180 | 6.1% | 1,350 | 2.27 | Village |
| South Bloomfield | 14 | 3,000 | 2,149 | 6.01% | 750 | 4 | Village |
| Baltimore | 15 | 2,995 | 2,984 | 0.07% | 1,341 | 2.23 | Village |
| Beechwood Trails | 16 | 2,876 | 3,040 | -0.35% | 809 | 3.56 | CDP |
| Amanda township | 17 | 2,776 | 2,691 | 0.84% | 75 | 36.88 | Township |
| Richland township | 18 | 2,390 | 2,343 | 0.55% | 97 | 24.73 | Township |
| Carroll township | 19 | 2,063 | 2,106 | -0.43% | 61 | 33.69 | Township |
| Amanda township | 20 | 2,041 | 2,071 | -0.24% | 61 | 33.31 | Township |
| Bremen | 21 | 1,514 | 1,483 | 0.4% | 1,758 | 0.86 | Village |
| Logan Elm Village | 22 | 1,249 | 1,021 | 0.73% | 3,441 | 0.36 | CDP |
| Fairfield Beach | 23 | 1,240 | 1,145 | -0.24% | 1,893 | 0.66 | CDP |
| Thornport | 24 | 1,049 | 946 | 0.29% | 873 | 1.20 | CDP |
| Amanda township | 25 | 1,029 | 1,065 | -0.87% | 37 | 27.73 | Township |
| Hide-A-Way Hills | 26 | 1,024 | 833 | 1.49% | 393 | 2.61 | CDP |
| Millersport | 27 | 973 | 978 | -0.1% | 1,046 | 0.93 | Village |
| Pleasantville | 28 | 955 | 945 | 0.21% | 3,524 | 0.27 | Village |
| Amanda | 29 | 686 | 670 | 0.44% | 2,164 | 0.32 | Village |
| Thurston | 30 | 603 | 607 | -0.17% | 1,493 | 0.40 | Village |
| Stoutsville | 31 | 575 | 579 | -0.17% | 497 | 1.16 | Village |
| Carroll | 32 | 498 | 502 | -0.2% | 792 | 0.63 | Village |
| Hamburg | 33 | 477 | 485 | 6.95% | 198 | 2.40 | CDP |
| Jersey | 34 | 424 | 483 | 7.07% | 259 | 1.64 | CDP |
| Sugar Grove | 35 | 423 | 428 | -0.24% | 1,378 | 0.31 | Village |
| Rushville | 36 | 302 | 306 | -0.33% | 1,258 | 0.24 | Village |
| Darbyville | 37 | 191 | 185 | 0.53% | 370 | 0.52 | Village |
| West Rushville | 38 | 165 | 165 | 0% | 2,538 | 0.07 | Village |
Violet township is the largest city in Fairfield County, with a population of 51,643.
West Rushville is the smallest city in Fairfield County.
There are 38 cities in Fairfield County, Ohio.