5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mount Vernon | 1 | 6,270 | 6,482 | -0.56% | 2,179 | 3 | City |
| Poseyville | 2 | 969 | 965 | 0.1% | 1,502 | 1 | Town |
| New Harmony | 3 | 681 | 695 | -0.29% | 836 | 1 | Town |
| Cynthiana | 4 | 554 | 554 | 0% | 1,388 | 0 | Town |
| Griffin | 5 | 141 | 143 | 0% | 2,074 | 0 | Town |
Mount Vernon is the largest city in Posey County, with a population of 6,270.
Griffin is the smallest city in Posey County, with a population of 141.
There are 5 cities in Posey County, Indiana.