17 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Brazil | 1 | 8,711 | 8,567 | 0.43% | 1,347 | 6 | Township |
| Brazil | 2 | 8,279 | 8,158 | 0.24% | 2,245 | 4 | City |
| Posey | 3 | 4,020 | 4,052 | -0.2% | 115 | 35 | Township |
| Jackson | 4 | 2,803 | 2,834 | -0.18% | 80 | 35 | Township |
| Harrison | 5 | 2,163 | 2,163 | -0.05% | 35 | 62 | Township |
| Dick Johnson | 6 | 1,323 | 1,328 | -0.23% | 62 | 21 | Township |
| Harmony | 7 | 1,226 | 1,229 | 0.08% | 35 | 35 | Township |
| Perry | 8 | 909 | 915 | -0.11% | 20 | 45 | Township |
| Sugar Ridge | 9 | 902 | 921 | -0.44% | 33 | 28 | Township |
| Clay City | 10 | 888 | 876 | 0.23% | 1,647 | 1 | Town |
| Knightsville | 11 | 691 | 699 | -0.14% | 666 | 1 | Town |
| Harmony | 12 | 670 | 678 | -0.15% | 815 | 1 | Town |
| Harmony | 13 | 496 | 515 | -1% | 24 | 21 | Township |
| Staunton | 14 | 467 | 470 | 0% | 1,428 | 0 | Town |
| Cass | 15 | 338 | 342 | -0.29% | 28 | 12 | Township |
| Carbon | 16 | 257 | 260 | 0% | 1,725 | 0 | Town |
| Center Point | 17 | 209 | 214 | -0.48% | 282 | 1 | Town |
Brazil is the largest city in Clay County, with a population of 8,711.
Center Point is the smallest city in Clay County, with a population of 209.
There are 17 cities in Clay County, Indiana.