| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sisseton | 1 | 2,402 | 2,471 | -0.46% | 1,510 | 2 | City |
| Wilmot | 2 | 421 | 433 | -0.47% | 790 | 1 | City |
| Rosholt | 3 | 367 | 381 | -0.81% | 1,240 | 0 | Town |
| Summit | 4 | 274 | 285 | -0.72% | 500 | 1 | Town |
| New Effington | 5 | 225 | 233 | -0.44% | 862 | 0 | Town |
| Peever | 6 | 171 | 176 | -0.58% | 1,379 | 0 | Town |
| Claire City | 7 | 80 | 83 | -1.23% | 437 | 0 | Town |
| Corona | 8 | 73 | 66 | 1.39% | 289 | 0 | Town |
| Ortley | 9 | 55 | 51 | 0% | 25 | 2 | Town |
| White Rock | 10 | 7 | 7 | 0% | 4.0 | 2 | Town |
Sisseton is the largest city in Roberts County, with a population of 2,402.
White Rock is the smallest city in Roberts County, with a population of 7.
There are 10 cities in Roberts County, South Dakota.