10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clay Center | 1 | 4,026 | 4,196 | -0.84% | 1,262 | 3.19 | City |
| Wakefield | 2 | 831 | 861 | -0.72% | 1,672 | 0.50 | City |
| Green township | 3 | 215 | 203 | 0.47% | 4 | 48.19 | Township |
| Morganville | 4 | 183 | 182 | 0% | 540 | 0.34 | City |
| Detroit | 5 | 145 | 151 | 1.4% | 296 | 0.49 | CDP |
| Green | 6 | 93 | 97 | -1.06% | 477 | 0.20 | City |
| Longford | 7 | 69 | 73 | -1.43% | 486 | 0.14 | City |
| Manchester | 8 | 49 | 48 | 0% | 306 | 0.16 | City |
| Vining | 9 | 39 | 41 | 0% | 182 | 0.21 | City |
| Oak Hill | 10 | 25 | 25 | 0% | 490 | 0.05 | City |
Clay Center is the largest city in Clay County, with a population of 4,026.
Oak Hill is the smallest city in Clay County.
There are 10 cities in Clay County, Kansas.