8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Carmel | 1 | 34,127 | 33,604 | 0.4% | 951 | 36 | Town |
| Southeast | 2 | 18,490 | 18,044 | 0.82% | 583 | 32 | Town |
| Putnam Valley | 3 | 11,776 | 11,738 | 0.27% | 286 | 41 | Town |
| Patterson | 4 | 11,638 | 11,523 | 0.41% | 361 | 32 | Town |
| Philipstown | 5 | 9,915 | 9,819 | 0.34% | 203 | 49 | Town |
| Brewster | 6 | 2,503 | 2,507 | -0.04% | 5,098 | 0 | Village |
| Cold Spring | 7 | 1,997 | 1,984 | 0.1% | 3,362 | 1 | Village |
| Nelsonville | 8 | 633 | 623 | 0.32% | 612 | 1 | Village |
Carmel is the largest city in Putnam County, with a population of 34,127.
Nelsonville is the smallest city in Putnam County, with a population of 633.
There are 8 cities in Putnam County, New York.