| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| McLaughlin | 1 | 546 | 567 | -0.91% | 1,351 | 0 | City |
| Fort Yates | 2 | 165 | 177 | -1.2% | 2,750 | 0 | City |
| Selfridge | 3 | 117 | 126 | -1.68% | 397 | 0 | City |
| Solen | 4 | 65 | 70 | -1.52% | 195 | 0 | City |
McLaughlin is the largest city in Sioux County, with a population of 546.
Solen is the smallest city in Sioux County, with a population of 65.
There are 4 cities in Sioux County, North Dakota.