43 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clear Creek township | 1 | 38,335 | 36,413 | 0.84% | 838 | 45.76 | Township |
| Mason | 2 | 36,178 | 34,882 | 0.72% | 1,878 | 19.26 | City |
| Franklin township | 3 | 33,044 | 31,683 | 0.77% | 1,004 | 32.91 | Township |
| Lebanon | 4 | 22,255 | 20,864 | 1.26% | 1,689 | 13.18 | City |
| Springboro | 5 | 19,704 | 19,131 | 0.59% | 2,140 | 9.21 | City |
| Turtlecreek township | 6 | 17,730 | 17,765 | -0.06% | 294 | 60.39 | Township |
| Franklin | 7 | 11,631 | 11,685 | -0.09% | 1,260 | 9.23 | City |
| Franklin township | 8 | 10,859 | 11,428 | -0.92% | 1,592 | 6.82 | Township |
| Landen | 9 | 8,491 | 7,882 | 1.36% | 4,187 | 2.03 | CDP |
| South Lebanon | 10 | 7,017 | 6,456 | 1.62% | 2,046 | 3.43 | Village |
| Union township | 11 | 6,797 | 6,288 | 1.39% | 510 | 13.33 | Township |
| Franklin township | 12 | 6,364 | 6,289 | 0.27% | 509 | 12.50 | Township |
| Harlan township | 13 | 5,331 | 4,952 | 1.31% | 117 | 45.45 | Township |
| Franklin township | 14 | 4,766 | 4,819 | -0.17% | 207 | 23.02 | Township |
| Franklin township | 15 | 4,226 | 4,237 | -0.02% | 118 | 35.96 | Township |
| Franklin township | 16 | 3,715 | 3,608 | 0.62% | 94 | 39.39 | Township |
| Franklin township | 17 | 3,479 | 3,490 | 0.2% | 141 | 24.72 | Township |
| Washington township | 18 | 2,984 | 2,767 | 1.32% | 88 | 33.90 | Township |
| Waynesville | 19 | 2,900 | 2,679 | 1.54% | 1,227 | 2.36 | Village |
| Franklin township | 20 | 2,610 | 2,508 | 0.89% | 105 | 24.88 | Township |
| Franklin township | 21 | 2,295 | 2,305 | -0.09% | 63 | 36.72 | Township |
| Morrow | 22 | 2,228 | 2,063 | 1.5% | 1,094 | 2.04 | Village |
| Franklin township | 23 | 2,208 | 2,128 | 0.68% | 90 | 24.55 | Township |
| Loveland Park | 24 | 1,899 | 2,388 | 1.33% | 1,469 | 1.29 | CDP |
| Franklin township | 25 | 1,710 | 1,702 | 0.18% | 64 | 26.87 | Township |
| Franklin township | 26 | 1,696 | 1,710 | -0.18% | 81 | 21.05 | Township |
| Franklin township | 27 | 1,651 | 1,618 | 0.61% | 60 | 27.45 | Township |
| Maineville | 28 | 1,536 | 1,415 | 1.59% | 967 | 1.59 | Village |
| Franklin township | 29 | 1,446 | 1,446 | 0.14% | 41 | 35 | Township |
| Massie township | 30 | 1,269 | 1,190 | 1.36% | 69 | 18.44 | Township |
| Franklin township | 31 | 1,183 | 1,147 | 0.85% | 49 | 24.38 | Township |
| Franklin township | 32 | 1,162 | 1,183 | -0.34% | 46 | 25.24 | Township |
| Kings Mills | 33 | 1,119 | 1,164 | -1.15% | 994 | 1.13 | CDP |
| Franklin township | 34 | 1,026 | 1,037 | -0.19% | 19 | 54.08 | Township |
| Mason township | 35 | 947 | 985 | -0.53% | 24 | 39.40 | Township |
| Lebanon township | 36 | 883 | 902 | -0.67% | 25 | 35.83 | Township |
| Franklin township | 37 | 734 | 759 | -0.68% | 32 | 22.99 | Township |
| Franklin township | 38 | 667 | 686 | -0.45% | 23 | 28.65 | Township |
| Harveysburg | 39 | 578 | 555 | 0.87% | 581 | 0.99 | Village |
| Roachester | 40 | 548 | 578 | 7.24% | 419 | 1.31 | CDP |
| Franklin township | 41 | 512 | 542 | -1.54% | 25 | 20.47 | Township |
| Franklin township | 42 | 361 | 370 | -0.28% | 15 | 23.78 | Township |
| Pleasant Plain | 43 | 139 | 129 | 1.46% | 858 | 0.16 | Village |
Clear Creek township is the largest city in Warren County, with a population of 38,335.
Pleasant Plain is the smallest city in Warren County.
There are 43 cities in Warren County, Ohio.