4 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Liberty | 1 | 1,950 | 2,043 | -0.76% | 2,478 | 1 | Town |
| West College Corner | 2 | 505 | 526 | -0.59% | 1,891 | 0 | Town |
| Spring Grove | 3 | 331 | 333 | 0% | 1,089 | 0 | Town |
| Whitewater | 4 | 71 | 71 | 0% | 899 | 0 | Town |
Liberty is the largest city in Union County, with a population of 1,950.
Whitewater is the smallest city in Union County, with a population of 71.
There are 4 cities in Union County, Indiana.