| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Plattsburgh | 1 | 19,710 | 19,825 | -0.17% | 3,671 | 5 | City |
| Plattsburgh | 2 | 11,784 | 11,864 | 0.31% | 259 | 46 | Town |
| Peru | 3 | 6,672 | 6,772 | 0.04% | 85 | 79 | Town |
| Champlain | 4 | 5,574 | 5,734 | -0.16% | 109 | 51 | Town |
| Beekmantown | 5 | 5,395 | 5,500 | -0.02% | 89 | 60 | Town |
| Schuyler Falls | 6 | 4,981 | 4,840 | 0.52% | 135 | 37 | Town |
| Chazy | 7 | 4,041 | 4,093 | 0.15% | 75 | 54 | Town |
| Saranac | 8 | 3,794 | 3,853 | 0.08% | 33 | 115 | Town |
| Dannemora | 9 | 3,471 | 4,042 | 5.47% | 59 | 59 | Town |
| Mooers | 10 | 3,466 | 3,457 | 0.49% | 40 | 87 | Town |
| Au Sable | 11 | 3,121 | 3,181 | -0.1% | 80 | 39 | Town |
| Altona | 12 | 2,518 | 2,627 | -0.16% | 25 | 101 | Town |
| Dannemora | 13 | 2,332 | 3,297 | -8.98% | 1,932 | 1 | Village |
| Rouses Point | 14 | 2,163 | 2,250 | -0.73% | 1,236 | 2 | Village |
| Ellenburg | 15 | 1,787 | 1,838 | -0.06% | 17 | 107 | Town |
| Black Brook | 16 | 1,417 | 1,440 | 0% | 11 | 130 | Town |
| Champlain | 17 | 1,112 | 1,161 | -0.89% | 763 | 1 | Village |
Plattsburgh is the largest city in Clinton County, with a population of 19,710.
Champlain is the smallest city in Clinton County, with a population of 1,112.
There are 17 cities in Clinton County, New York.