42 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Center | 1 | 3,338 | 3,450 | -0.92% | 81 | 41 | Township |
| Center | 2 | 3,338 | 3,440 | -0.92% | 81 | 41 | Township |
| Jerusalem | 3 | 2,904 | 2,896 | 0.07% | 98 | 30 | Township |
| Jerusalem | 4 | 2,904 | 2,902 | 0.07% | 98 | 30 | Township |
| Woodsfield | 5 | 2,130 | 2,209 | -0.7% | 1,057 | 2 | Village |
| Woodsfield | 6 | 2,130 | 2,202 | -0.7% | 1,057 | 2 | Village |
| Sunsbury | 7 | 1,228 | 1,279 | -0.97% | 43 | 28 | Township |
| Sunsbury | 8 | 1,228 | 1,276 | -0.97% | 43 | 28 | Township |
| Malaga | 9 | 1,015 | 1,051 | -0.88% | 35 | 29 | Township |
| Malaga | 10 | 1,015 | 1,049 | -0.88% | 35 | 29 | Township |
| Lee | 11 | 870 | 900 | -0.8% | 50 | 17 | Township |
| Lee | 12 | 870 | 898 | -0.8% | 50 | 17 | Township |
| Ohio | 13 | 822 | 851 | -0.84% | 36 | 23 | Township |
| Ohio | 14 | 822 | 849 | -0.84% | 36 | 23 | Township |
| Matamoras (New Matamoras) | 15 | 680 | 704 | -0.73% | 1,954 | 0 | Village |
| Matamoras (New Matamoras) | 16 | 680 | 703 | -0.73% | 1,954 | 0 | Village |
| Adams | 17 | 625 | 636 | -0.48% | 28 | 22 | Township |
| Adams | 18 | 625 | 635 | -0.48% | 28 | 22 | Township |
| Summit | 19 | 575 | 603 | -1.2% | 25 | 23 | Township |
| Summit | 20 | 575 | 602 | -1.2% | 25 | 23 | Township |
| Seneca | 21 | 418 | 434 | -0.71% | 19 | 22 | Township |
| Seneca | 22 | 418 | 433 | -0.71% | 19 | 22 | Township |
| Switzerland | 23 | 408 | 418 | -0.73% | 15 | 27 | Township |
| Switzerland | 24 | 408 | 417 | -0.73% | 15 | 27 | Township |
| Washington | 25 | 395 | 411 | -1% | 13 | 31 | Township |
| Washington | 26 | 395 | 410 | -1% | 13 | 31 | Township |
| Sardis | 27 | 344 | 629 | -3.91% | 273 | 1 | CDP |
| Beallsville | 28 | 341 | 352 | -0.58% | 939 | 0 | Village |
| Beallsville | 29 | 341 | 351 | -0.58% | 939 | 0 | Village |
| Benton | 30 | 271 | 280 | -0.73% | 12 | 23 | Township |
| Benton | 31 | 271 | 280 | -0.73% | 12 | 23 | Township |
| Clarington | 32 | 269 | 280 | -0.74% | 235 | 1 | Village |
| Clarington | 33 | 269 | 279 | -0.74% | 235 | 1 | Village |
| Jerusalem | 34 | 120 | 124 | -0.83% | 496 | 0 | Village |
| Jerusalem | 35 | 120 | 124 | -0.83% | 496 | 0 | Village |
| Hannibal | 36 | 118 | 295 | -14.49% | 106 | 1 | CDP |
| Antioch | 37 | 72 | 75 | -1.37% | 699 | 0 | Village |
| Antioch | 38 | 72 | 75 | -1.37% | 699 | 0 | Village |
| Stafford | 39 | 66 | 69 | -1.49% | 194 | 0 | Village |
| Stafford | 40 | 66 | 69 | -1.49% | 194 | 0 | Village |
| Miltonsburg | 41 | 38 | 40 | -2.56% | 521 | 0 | Village |
| Miltonsburg | 42 | 38 | 40 | -2.56% | 521 | 0 | Village |
Center is the largest city in Monroe County, with a population of 3,338.
Miltonsburg is the smallest city in Monroe County, with a population of 38.
There are 42 cities in Monroe County, Ohio.