9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wilmington | 1 | 12,628 | 12,661 | -0.04% | 976 | 13 | City |
| Blanchester | 2 | 4,224 | 4,230 | -0.02% | 1,033 | 4 | Village |
| Sabina | 3 | 2,450 | 2,495 | -0.28% | 2,083 | 1 | Village |
| New Vienna | 4 | 1,088 | 1,115 | -0.37% | 1,357 | 1 | Village |
| Corwin | 5 | 542 | 490 | 1.69% | 1,647 | 0 | Village |
| Clarksville | 6 | 536 | 536 | 0% | 1,150 | 0 | Village |
| Martinsville | 7 | 403 | 415 | -0.49% | 1,092 | 0 | Village |
| Midland | 8 | 296 | 307 | -0.67% | 831 | 0 | Village |
| Port William | 9 | 218 | 223 | -0.46% | 2,000 | 0 | Village |
Wilmington is the largest city in Clinton County, with a population of 12,628.
Port William is the smallest city in Clinton County, with a population of 218.
There are 9 cities in Clinton County, Ohio.