27 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Delhi | 1 | 5,370 | 4,782 | -0.06% | 84 | 64 | Town |
| Sidney | 2 | 5,306 | 5,526 | -0.95% | 106 | 50 | Town |
| Walton | 3 | 5,036 | 5,258 | -1.02% | 52 | 97 | Town |
| Delhi | 4 | 3,653 | 2,779 | 4.16% | 1,150 | 3 | Village |
| Sidney | 5 | 3,567 | 3,705 | -0.64% | 1,499 | 2 | Village |
| Davenport | 6 | 2,887 | 2,943 | -0.59% | 56 | 52 | Town |
| Walton | 7 | 2,809 | 2,914 | -0.6% | 1,822 | 2 | Village |
| Hancock | 8 | 2,681 | 2,757 | -0.78% | 17 | 159 | Town |
| Franklin | 9 | 2,229 | 2,285 | -0.67% | 27 | 81 | Town |
| Roxbury | 10 | 2,178 | 2,245 | -0.91% | 25 | 87 | Town |
| Stamford | 11 | 1,958 | 1,995 | -0.51% | 40 | 49 | Town |
| Colchester | 12 | 1,736 | 1,775 | -0.8% | 13 | 137 | Town |
| Kortright | 13 | 1,479 | 1,543 | -1.07% | 24 | 62 | Town |
| Meredith | 14 | 1,471 | 1,488 | -0.68% | 25 | 58 | Town |
| Harpersfield | 15 | 1,387 | 1,448 | -1% | 33 | 42 | Town |
| Tompkins | 16 | 1,233 | 1,289 | -1.04% | 13 | 98 | Town |
| Masonville | 17 | 1,207 | 1,239 | -0.82% | 22 | 54 | Town |
| Franklin | 18 | 1,141 | 1,146 | -0.09% | 7 | 170 | Town |
| Hamden | 19 | 1,104 | 1,133 | -0.63% | 18 | 60 | Town |
| Andes | 20 | 1,074 | 1,117 | -1.01% | 10 | 109 | Town |
| Stamford | 21 | 1,053 | 1,085 | -0.47% | 790 | 1 | Village |
| Hancock | 22 | 878 | 914 | -0.68% | 561 | 2 | Village |
| Bovina | 23 | 626 | 657 | -1.11% | 14 | 44 | Town |
| Margaretville | 24 | 473 | 529 | -1.87% | 680 | 1 | Village |
| Hobart | 25 | 381 | 398 | -0.78% | 765 | 0 | Village |
| Franklin | 26 | 269 | 280 | -0.74% | 794 | 0 | Village |
| Fleischmanns | 27 | 222 | 233 | -0.89% | 339 | 1 | Village |
Delhi is the largest city in Delaware County, with a population of 5,370.
Fleischmanns is the smallest city in Delaware County, with a population of 222.
There are 27 cities in Delaware County, New York.