39 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wellsville | 1 | 6,899 | 7,047 | -0.2% | 188 | 37 | Town |
| Alfred | 2 | 6,538 | 6,131 | -0.11% | 208 | 31 | Town |
| Alfred | 3 | 5,685 | 5,042 | 1.92% | 4,777 | 1 | Village |
| Wellsville | 4 | 4,510 | 4,632 | -0.44% | 1,861 | 2 | Village |
| Cuba | 5 | 3,054 | 3,124 | -0.52% | 87 | 35 | Town |
| Caneadea | 6 | 2,248 | 2,276 | -0.09% | 63 | 36 | Town |
| Amity | 7 | 2,127 | 2,173 | -0.09% | 62 | 34 | Town |
| Hume | 8 | 2,031 | 2,075 | -0.29% | 54 | 38 | Town |
| Bolivar | 9 | 1,961 | 2,027 | -0.51% | 55 | 36 | Town |
| Friendship | 10 | 1,934 | 1,941 | 0.1% | 53 | 36 | Town |
| Belfast | 11 | 1,639 | 1,638 | 0.43% | 45 | 36 | Town |
| Scio | 12 | 1,591 | 1,613 | -0.25% | 45 | 35 | Town |
| Genesee | 13 | 1,589 | 1,634 | -0.38% | 44 | 36 | Town |
| Andover | 14 | 1,565 | 1,616 | -0.45% | 40 | 39 | Town |
| Almond | 15 | 1,504 | 1,507 | 0.33% | 33 | 46 | Town |
| Cuba | 16 | 1,486 | 1,540 | -0.6% | 1,222 | 1 | Village |
| Angelica | 17 | 1,282 | 1,273 | 0.39% | 35 | 36 | Town |
| Willing | 18 | 1,243 | 1,281 | -0.32% | 34 | 36 | Town |
| Independence | 19 | 1,090 | 1,083 | 0.37% | 32 | 34 | Town |
| Rushford | 20 | 1,073 | 1,073 | 0.19% | 30 | 35 | Town |
| Wirt | 21 | 1,019 | 1,047 | -0.29% | 28 | 36 | Town |
| Burns | 22 | 1,016 | 1,033 | -0.1% | 37 | 27 | Town |
| Centerville | 23 | 990 | 926 | 1.85% | 28 | 35 | Town |
| Bolivar | 24 | 989 | 1,024 | -0.6% | 1,241 | 1 | Village |
| Andover | 25 | 880 | 912 | -0.56% | 879 | 1 | Village |
| Belmont | 26 | 824 | 853 | -0.6% | 827 | 1 | Village |
| New Hudson | 27 | 794 | 795 | -0.13% | 22 | 36 | Town |
| North Hornell | 28 | 758 | 779 | -0.39% | 1,544 | 0 | Village |
| Alma | 29 | 755 | 776 | -0.4% | 21 | 36 | Town |
| Angelica | 30 | 701 | 718 | -0.43% | 326 | 2 | Village |
| Allen | 31 | 524 | 487 | 2.54% | 14 | 36 | Town |
| Granger | 32 | 521 | 516 | 0% | 16 | 32 | Town |
| Grove | 33 | 505 | 492 | 0.8% | 15 | 33 | Town |
| Canaseraga | 34 | 448 | 465 | -0.67% | 422 | 1 | Village |
| Richburg | 35 | 401 | 416 | -0.5% | 446 | 1 | Village |
| Almond | 36 | 392 | 404 | -0.51% | 695 | 1 | Village |
| Ward | 37 | 330 | 329 | 0% | 11 | 29 | Town |
| West Almond | 38 | 278 | 277 | 0.36% | 8 | 36 | Town |
| Birdsall | 39 | 188 | 189 | 0% | 5 | 36 | Town |
Wellsville is the largest city in Allegany County, with a population of 6,899.
Birdsall is the smallest city in Allegany County, with a population of 188.
There are 39 cities in Allegany County, New York.