3 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Vermillion | 1 | 11,953 | 11,725 | 0.32% | 2,564 | 5 | City |
| Irene | 2 | 433 | 426 | 0.23% | 1,698 | 0 | City |
| Wakonda | 3 | 341 | 346 | -0.29% | 883 | 0 | Town |
Vermillion is the largest city in Clay County, with a population of 11,953.
Wakonda is the smallest city in Clay County, with a population of 341.
There are 3 cities in Clay County, South Dakota.