| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Brookville | 1 | 2,670 | 2,618 | 0.26% | 1,911 | 1 | Town |
| Oldenburg | 2 | 652 | 643 | 0.15% | 1,516 | 0 | Town |
| Laurel | 3 | 415 | 408 | 0.24% | 1,744 | 0 | Town |
| Cedar Grove | 4 | 148 | 147 | 0% | 980 | 0 | Town |
Brookville is the largest city in Franklin County, with a population of 2,670.
Cedar Grove is the smallest city in Franklin County, with a population of 148.
There are 4 cities in Franklin County, Indiana.