18 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Center township | 1 | 17,243 | 17,602 | -0.17% | 836 | 20.62 | Township |
| Frankfort | 2 | 16,215 | 16,700 | -0.59% | 2,013 | 8.05 | City |
| Ross township | 3 | 2,789 | 2,810 | -0.04% | 94 | 29.58 | Township |
| Michigan township | 4 | 1,529 | 1,563 | -0.33% | 43 | 35.82 | Township |
| Rossville | 5 | 1,494 | 1,509 | -0.2% | 3,255 | 0.46 | Town |
| Perry township | 6 | 1,471 | 1,488 | -0.07% | 44 | 33.12 | Township |
| Kirklin township | 7 | 1,223 | 1,233 | 0.08% | 35 | 35.06 | Township |
| Mulberry | 8 | 1,209 | 1,229 | -0.33% | 2,264 | 0.53 | Town |
| Jackson township | 9 | 1,149 | 1,168 | -0.26% | 26 | 43.45 | Township |
| Union township | 10 | 921 | 933 | -0.22% | 47 | 19.80 | Township |
| Owen township | 11 | 884 | 894 | -0.11% | 35 | 24.98 | Township |
| Forest township | 12 | 747 | 749 | 0.13% | 28 | 26.43 | Township |
| Kirklin | 13 | 700 | 712 | -0.28% | 1,663 | 0.42 | Town |
| Colfax | 14 | 694 | 704 | -0.29% | 1,876 | 0.37 | Town |
| Sugar Creek township | 15 | 450 | 453 | 0.22% | 17 | 25.84 | Township |
| Johnson township | 16 | 445 | 455 | -0.45% | 17 | 26.67 | Township |
| Michigantown | 17 | 416 | 436 | -0.95% | 1,535 | 0.27 | Town |
| Colfax township | 18 | 173 | 165 | 1.17% | 5 | 36.53 | Township |
Center township is the largest city in Clinton County, with a population of 17,243.
Colfax township is the smallest city in Clinton County.
There are 18 cities in Clinton County, Indiana.