Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| German Flatts | 1 | 12,044 | 12,239 | -0.29% | 357 | 33.7 | Town |
| Herkimer | 2 | 9,440 | 9,550 | -0.5% | 298 | 31.7 | Town |
| Ilion | 3 | 7,533 | 7,669 | -0.45% | 3,022 | 2.5 | Village |
| Herkimer | 4 | 7,218 | 7,286 | -0.24% | 2,789 | 2.6 | Village |
| Frankfort | 5 | 6,871 | 6,992 | -0.28% | 189 | 36.4 | Town |
| Little Falls | 6 | 4,494 | 4,581 | -0.49% | 1,171 | 3.8 | City |
| Mohawk | 7 | 3,519 | 3,565 | -0.28% | 101 | 34.7 | Town |
| Schuyler | 8 | 3,247 | 3,301 | -0.25% | 81 | 39.9 | Town |
| Manheim | 9 | 3,037 | 3,080 | -0.23% | 104 | 29.1 | Town |
| Mohawk | 10 | 2,365 | 2,415 | -0.55% | 2,697 | 0.9 | Village |
| Frankfort | 11 | 2,277 | 2,323 | -0.52% | 2,246 | 1.0 | Village |
| Russia | 12 | 2,277 | 2,265 | 0.4% | 40 | 57.0 | Town |
| Poland | 13 | 2,174 | 2,209 | 0.14% | 60 | 36.5 | Town |
| Newport | 14 | 2,103 | 2,142 | -0.28% | 66 | 32.0 | Town |
| Dolgeville | 15 | 2,003 | 2,045 | -0.55% | 1,118 | 1.8 | Village |
| Winfield | 16 | 1,883 | 1,894 | 0% | 80 | 23.6 | Town |
| Salisbury | 17 | 1,828 | 1,827 | 0.16% | 17 | 107.4 | Town |
| Webb | 18 | 1,814 | 1,796 | 0.44% | 4 | 451.4 | Town |
| Columbia | 19 | 1,592 | 1,567 | 0.76% | 45 | 35.1 | Town |
| Little Falls | 20 | 1,469 | 1,496 | -0.27% | 66 | 22.3 | Town |
| Fairfield | 21 | 1,444 | 1,469 | -0.28% | 35 | 41.3 | Town |
| Litchfield | 22 | 1,440 | 1,442 | 0.21% | 48 | 30.0 | Town |
| Warren | 23 | 1,018 | 1,033 | -0.2% | 27 | 38.1 | Town |
| West Winfield | 24 | 731 | 745 | -0.54% | 802 | 0.9 | Village |
| Newport | 25 | 552 | 562 | -0.54% | 1,049 | 0.5 | Village |
| Poland | 26 | 480 | 488 | -0.41% | 884 | 0.5 | Village |
| Middleville | 27 | 426 | 434 | -0.47% | 557 | 0.8 | Village |
| Cold Brook | 28 | 258 | 266 | -0.77% | 588 | 0.4 | Village |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
German Flatts is the largest city in Herkimer County.
Cold Brook is the smallest city in Herkimer County.
There are 28 cities in Herkimer County, New York.