| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clay Center | 1 | 4,033 | 4,195 | -0.69% | 1,264 | 3 | City |
| Wakefield | 2 | 829 | 865 | -0.72% | 1,668 | 0 | City |
| Morganville | 3 | 181 | 180 | 0% | 534 | 0 | City |
| Green | 4 | 91 | 97 | -1.09% | 467 | 0 | City |
| Longford | 5 | 70 | 73 | -1.41% | 493 | 0 | City |
| Manchester | 6 | 49 | 48 | 0% | 306 | 0 | City |
| Vining | 7 | 42 | 42 | -2.33% | 196 | 0 | City |
| Oak Hill | 8 | 24 | 24 | 0% | 471 | 0 | City |
Clay Center is the largest city in Clay County, with a population of 4,033.
Oak Hill is the smallest city in Clay County, with a population of 24.
There are 8 cities in Clay County, Kansas.