7 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mount Vernon | 1 | 6,273 | 6,477 | -0.65% | 2,180 | 2.88 | City |
| Poseyville | 2 | 966 | 968 | 0% | 1,498 | 0.65 | Town |
| New Harmony | 3 | 680 | 694 | -0.44% | 834 | 0.81 | Town |
| Wadesville | 4 | 646 | 0 | 7.13% | 569 | 1.14 | CDP |
| Cynthiana | 5 | 547 | 551 | -0.18% | 1,371 | 0.40 | Town |
| Parkers Settlement | 6 | 506 | 591 | -2.69% | 289 | 1.75 | CDP |
| Griffin | 7 | 142 | 142 | 0% | 2,088 | 0.07 | Town |
Mount Vernon is the largest city in Posey County, with a population of 6,273.
Griffin is the smallest city in Posey County.
There are 7 cities in Posey County, Indiana.