5 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Randolph | 1 | 4,341 | 4,294 | 0.02% | 116 | 37 | Township |
| Rising Sun | 2 | 2,216 | 2,228 | -0.14% | 1,475 | 2 | City |
| Cass | 3 | 697 | 687 | 0% | 38 | 19 | Township |
| Pike | 4 | 491 | 482 | 0.2% | 26 | 19 | Township |
| Union | 5 | 470 | 462 | 0.21% | 41 | 12 | Township |
Randolph is the largest city in Ohio County, with a population of 4,341.
Union is the smallest city in Ohio County, with a population of 470.
There are 5 cities in Ohio County, Indiana.