21 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Niagara Falls | 1 | 47,260 | 48,520 | -0.53% | 3,356 | 14 | City |
| North Tonawanda | 2 | 29,868 | 30,433 | -0.38% | 2,959 | 10 | City |
| Lockport | 3 | 20,652 | 20,501 | 0.45% | 461 | 45 | Town |
| Lockport | 4 | 20,285 | 20,829 | -0.53% | 2,415 | 8 | City |
| Wheatfield | 5 | 18,667 | 18,574 | 0.48% | 669 | 28 | Town |
| Lewiston | 6 | 15,550 | 15,917 | -0.66% | 419 | 37 | Town |
| Newfane | 7 | 9,176 | 9,259 | -0.12% | 177 | 52 | Town |
| Niagara | 8 | 7,686 | 7,882 | -0.34% | 810 | 9 | Town |
| Royalton | 9 | 7,445 | 7,512 | -0.05% | 106 | 70 | Town |
| Pendleton | 10 | 7,250 | 7,028 | 1.61% | 268 | 27 | Town |
| Porter | 11 | 6,449 | 6,500 | 0.09% | 195 | 33 | Town |
| Wilson | 12 | 5,740 | 5,834 | -0.14% | 116 | 49 | Town |
| Cambria | 13 | 5,733 | 5,741 | 0.12% | 144 | 40 | Town |
| Hartland | 14 | 3,818 | 3,867 | 0.1% | 73 | 52 | Town |
| Somerset | 15 | 2,553 | 2,596 | -0.12% | 69 | 37 | Town |
| Lewiston | 16 | 2,489 | 2,529 | -0.32% | 2,269 | 1 | Village |
| Barker | 17 | 2,447 | 2,501 | -0.16% | 59 | 41 | Town |
| Youngstown | 18 | 1,821 | 1,859 | -0.44% | 1,685 | 1 | Village |
| Middleport | 19 | 1,677 | 1,729 | -0.65% | 1,923 | 1 | Village |
| Wilson | 20 | 1,213 | 1,242 | -0.49% | 1,492 | 1 | Village |
| Barker | 21 | 566 | 584 | -0.7% | 1,348 | 0 | Village |
Niagara Falls is the largest city in Niagara County, with a population of 47,260.
Barker is the smallest city in Niagara County, with a population of 566.
There are 21 cities in Niagara County, New York.