15 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Brookville | 1 | 5,738 | 5,695 | -0.21% | 90 | 64 | Township |
| Ray | 2 | 4,379 | 4,322 | -0.21% | 111 | 40 | Township |
| Whitewater | 3 | 2,727 | 2,712 | -0.26% | 78 | 35 | Township |
| Brookville | 4 | 2,671 | 2,623 | 0.3% | 1,912 | 1 | Town |
| Laurel | 5 | 1,420 | 1,409 | -0.28% | 45 | 32 | Township |
| Springfield | 6 | 1,189 | 1,118 | 0.76% | 33 | 36 | Township |
| Posey | 7 | 1,028 | 1,015 | -0.1% | 57 | 18 | Township |
| Blooming Grove | 8 | 1,025 | 1,021 | -0.39% | 48 | 21 | Township |
| Salt Creek | 9 | 995 | 986 | -0.3% | 37 | 27 | Township |
| Metamora | 10 | 935 | 921 | -0.11% | 48 | 19 | Township |
| Oldenburg | 11 | 649 | 642 | 0.15% | 1,509 | 0 | Town |
| Fairfield | 12 | 535 | 511 | 0.38% | 40 | 13 | Township |
| Laurel | 13 | 413 | 409 | 0.24% | 1,735 | 0 | Town |
| Bath | 14 | 355 | 353 | 0% | 19 | 18 | Township |
| Cedar Grove | 15 | 146 | 146 | 0% | 967 | 0 | Town |
Brookville is the largest city in Franklin County, with a population of 5,738.
Cedar Grove is the smallest city in Franklin County, with a population of 146.
There are 15 cities in Franklin County, Indiana.