8 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Carmel | 1 | 34,262 | 33,604 | 0.4% | 955 | 36 | Town |
| Southeast | 2 | 18,640 | 18,044 | 0.81% | 588 | 32 | Town |
| Putnam Valley | 3 | 11,808 | 11,738 | 0.27% | 287 | 41 | Town |
| Patterson | 4 | 11,685 | 11,523 | 0.4% | 363 | 32 | Town |
| Philipstown | 5 | 9,949 | 9,819 | 0.34% | 204 | 49 | Town |
| Brewster | 6 | 2,502 | 2,507 | -0.04% | 5,096 | 0 | Village |
| Cold Spring | 7 | 2,000 | 1,984 | 0.15% | 3,367 | 1 | Village |
| Nelsonville | 8 | 635 | 623 | 0.32% | 614 | 1 | Village |
Carmel is the largest city in Putnam County, with a population of 34,262.
Nelsonville is the smallest city in Putnam County, with a population of 635.
There are 8 cities in Putnam County, New York.