15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Yankton | 1 | 15,765 | 15,427 | 0.43% | 1,812 | 8.70 | City |
| Utica township | 2 | 748 | 745 | 0.13% | 21 | 35.70 | Township |
| Gayville | 3 | 376 | 381 | -0.27% | 1,834 | 0.20 | Town |
| Mission Hill township | 4 | 356 | 358 | -0.28% | 10 | 35.01 | Township |
| Volin township | 5 | 248 | 250 | -0.4% | 7 | 35.55 | Township |
| Jamesville township | 6 | 217 | 217 | 0% | 6 | 36.16 | Township |
| Gayville township | 7 | 193 | 190 | 0.52% | 6 | 31.08 | Township |
| Mayfield township | 8 | 187 | 181 | 1.08% | 5 | 36.51 | Township |
| Mission Hill | 9 | 183 | 193 | -1.08% | 558 | 0.33 | Town |
| Turkey Valley township | 10 | 173 | 167 | 1.17% | 5 | 35.75 | Township |
| Marindahl township | 11 | 166 | 160 | 1.22% | 5 | 35.75 | Township |
| Walshtown township | 12 | 161 | 156 | 1.26% | 4 | 36.28 | Township |
| Volin | 13 | 157 | 156 | 0% | 797 | 0.20 | Town |
| Lesterville | 14 | 115 | 114 | 0% | 569 | 0.20 | Town |
| Utica | 15 | 71 | 71 | 0% | 269 | 0.26 | Town |
Yankton is the largest city in Yankton County, with a population of 15,765.
Utica is the smallest city in Yankton County.
There are 15 cities in Yankton County, South Dakota.