9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clay Center | 1 | 4,037 | 4,202 | -0.81% | 1,265 | 3 | City |
| Wakefield | 2 | 834 | 863 | -0.71% | 1,678 | 0 | City |
| Green | 3 | 221 | 203 | 1.38% | 5 | 48 | Township |
| Morganville | 4 | 180 | 182 | -0.55% | 531 | 0 | City |
| Green | 5 | 91 | 96 | -1.09% | 467 | 0 | City |
| Longford | 6 | 70 | 73 | -1.41% | 493 | 0 | City |
| Manchester | 7 | 51 | 49 | 0% | 319 | 0 | City |
| Vining | 8 | 38 | 40 | -2.56% | 178 | 0 | City |
| Oak Hill | 9 | 25 | 24 | 0% | 490 | 0 | City |
Clay Center is the largest city in Clay County, with a population of 4,037.
Oak Hill is the smallest city in Clay County, with a population of 25.
There are 9 cities in Clay County, Kansas.