3 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Harrison | 1 | 241 | 238 | 0.42% | 788 | 0.31 | Village |
| Harrison township | 2 | 79 | 74 | 2.6% | 2 | 35.85 | Township |
| Dudley | 3 | 9 | 21 | 12.5% | 84 | 0.11 | CDP |
Harrison is the largest city in Sioux County, with a population of 241.
Dudley is the smallest city in Sioux County.
There are 3 cities in Sioux County, Nebraska.