1 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Winnett | 1 | 199 | 188 | 1.02% | 195 | 1 | Town |
Winnett is the largest city in Petroleum County, with a population of 199.
Winnett is the smallest city in Petroleum County, with a population of 199.
There is 1 city in Petroleum County, Montana.