15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Yankton | 1 | 15,731 | 15,426 | 0.39% | 1,809 | 9 | City |
| Utica | 2 | 746 | 749 | -0.27% | 21 | 36 | Township |
| Gayville | 3 | 376 | 388 | -0.79% | 1,834 | 0 | Town |
| Mission Hill | 4 | 357 | 359 | -0.28% | 10 | 35 | Township |
| Volin | 5 | 242 | 244 | -0.41% | 7 | 36 | Township |
| Jamesville | 6 | 215 | 217 | -0.46% | 6 | 36 | Township |
| Mayfield | 7 | 182 | 181 | 0% | 5 | 37 | Township |
| Mission Hill | 8 | 179 | 191 | -1.65% | 546 | 0 | Town |
| Gayville | 9 | 177 | 182 | -1.67% | 6 | 31 | Township |
| Marindahl | 10 | 166 | 166 | -0.6% | 5 | 36 | Township |
| Turkey Valley | 11 | 163 | 166 | -1.21% | 5 | 36 | Township |
| Volin | 12 | 158 | 160 | -0.63% | 802 | 0 | Town |
| Walshtown | 13 | 154 | 155 | -0.65% | 4 | 36 | Township |
| Lesterville | 14 | 114 | 113 | 0% | 564 | 0 | Town |
| Utica | 15 | 69 | 71 | -1.43% | 261 | 0 | Town |
Yankton is the largest city in Yankton County, with a population of 15,731.
Utica is the smallest city in Yankton County, with a population of 69.
There are 15 cities in Yankton County, South Dakota.