21 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Niagara Falls | 1 | 47,008 | 48,520 | -0.53% | 3,338 | 14 | City |
| North Tonawanda | 2 | 29,755 | 30,433 | -0.38% | 2,948 | 10 | City |
| Lockport | 3 | 20,745 | 20,501 | 0.45% | 463 | 45 | Town |
| Lockport | 4 | 20,176 | 20,829 | -0.54% | 2,402 | 8 | City |
| Wheatfield | 5 | 18,756 | 18,574 | 0.48% | 672 | 28 | Town |
| Lewiston | 6 | 15,446 | 15,917 | -0.67% | 416 | 37 | Town |
| Newfane | 7 | 9,165 | 9,259 | -0.12% | 177 | 52 | Town |
| Niagara | 8 | 7,660 | 7,882 | -0.34% | 808 | 9 | Town |
| Royalton | 9 | 7,441 | 7,512 | -0.05% | 106 | 70 | Town |
| Pendleton | 10 | 7,365 | 7,028 | 1.59% | 272 | 27 | Town |
| Porter | 11 | 6,455 | 6,500 | 0.09% | 195 | 33 | Town |
| Cambria | 12 | 5,740 | 5,741 | 0.12% | 145 | 40 | Town |
| Wilson | 13 | 5,732 | 5,834 | -0.14% | 116 | 49 | Town |
| Hartland | 14 | 3,822 | 3,867 | 0.1% | 73 | 52 | Town |
| Somerset | 15 | 2,550 | 2,596 | -0.12% | 69 | 37 | Town |
| Lewiston | 16 | 2,481 | 2,529 | -0.32% | 2,262 | 1 | Village |
| Barker | 17 | 2,443 | 2,501 | -0.16% | 59 | 41 | Town |
| Youngstown | 18 | 1,814 | 1,859 | -0.38% | 1,678 | 1 | Village |
| Middleport | 19 | 1,667 | 1,729 | -0.6% | 1,912 | 1 | Village |
| Wilson | 20 | 1,207 | 1,242 | -0.49% | 1,485 | 1 | Village |
| Barker | 21 | 563 | 584 | -0.53% | 1,340 | 0 | Village |
Niagara Falls is the largest city in Niagara County, with a population of 47,008.
Barker is the smallest city in Niagara County, with a population of 563.
There are 21 cities in Niagara County, New York.