| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Yankton | 1 | 15,887 | 15,425 | 0.45% | 1,827 | 9 | City |
| Gayville | 2 | 372 | 388 | -0.8% | 1,815 | 0 | Town |
| Mission Hill | 3 | 185 | 193 | -1.07% | 564 | 0 | Town |
| Volin | 4 | 156 | 158 | -0.64% | 792 | 0 | Town |
| Lesterville | 5 | 110 | 110 | 0% | 545 | 0 | Town |
| Utica | 6 | 68 | 71 | -1.45% | 258 | 0 | Town |
Yankton is the largest city in Yankton County, with a population of 15,887.
Utica is the smallest city in Yankton County, with a population of 68.
There are 6 cities in Yankton County, South Dakota.