6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Farmerville | 1 | 3,234 | 3,364 | -0.8% | 560 | 5.78 | Town |
| Bernice | 2 | 1,280 | 1,355 | -1.16% | 395 | 3.24 | Town |
| Marion | 3 | 591 | 623 | -1.01% | 184 | 3.21 | Town |
| Spearsville | 4 | 117 | 124 | -0.85% | 49 | 2.37 | Village |
| Downsville | 5 | 109 | 119 | -1.8% | 147 | 0.74 | Village |
| Lillie | 6 | 106 | 110 | -0.93% | 55 | 1.93 | Village |
Farmerville is the largest city in Union Parish, with a population of 3,234.
Lillie is the smallest city in Union Parish.
There are 6 cities in Union Parish, Louisiana.