10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Cadiz | 1 | 2,922 | 3,059 | -0.92% | 333 | 8.78 | Village |
| Hopedale | 2 | 889 | 924 | -0.78% | 759 | 1.17 | Village |
| Scio | 3 | 641 | 671 | -0.93% | 1,151 | 0.56 | Village |
| Jewett | 4 | 529 | 553 | -0.94% | 1,039 | 0.51 | Village |
| Bowerston | 5 | 343 | 358 | -0.87% | 678 | 0.51 | Village |
| Freeport | 6 | 310 | 322 | -0.64% | 518 | 0.60 | Village |
| New Athens | 7 | 209 | 221 | -0.95% | 726 | 0.29 | Village |
| Harrisville | 8 | 170 | 177 | -0.58% | 1,118 | 0.15 | Village |
| Tippecanoe | 9 | 91 | 97 | -2.15% | 169 | 0.54 | CDP |
| Deersville | 10 | 64 | 66 | 0% | 186 | 0.34 | Village |
Cadiz is the largest city in Harrison County, with a population of 2,922.
Deersville is the smallest city in Harrison County.
There are 10 cities in Harrison County, Ohio.