23 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fort Wayne | 1 | 275,405 | 264,394 | 0.81% | 2,489 | 111 | City |
| Wayne | 2 | 111,985 | 107,647 | 0.96% | 2,659 | 42 | Township |
| St. Joseph | 3 | 79,940 | 76,488 | 1.04% | 2,274 | 35 | Township |
| Aboite | 4 | 44,154 | 42,174 | 1.08% | 1,329 | 33 | Township |
| Perry | 5 | 39,422 | 37,664 | 1.08% | 1,110 | 36 | Township |
| Adams | 6 | 35,767 | 34,181 | 1.07% | 1,080 | 33 | Township |
| New Haven | 7 | 16,341 | 15,635 | 0.87% | 1,373 | 12 | City |
| Cedar Creek | 8 | 14,348 | 13,711 | 1.08% | 416 | 34 | Township |
| Huntertown | 9 | 11,577 | 11,097 | 0.84% | 1,653 | 7 | Town |
| Springfield | 10 | 4,754 | 4,545 | 1.06% | 135 | 35 | Township |
| Eel River | 11 | 4,396 | 4,205 | 1.06% | 120 | 37 | Township |
| Leo-Cedarville | 12 | 3,792 | 3,636 | 0.82% | 1,018 | 4 | Town |
| Pleasant | 13 | 3,098 | 2,971 | 1.01% | 88 | 35 | Township |
| Lake | 14 | 2,917 | 2,794 | 1.04% | 82 | 36 | Township |
| Maumee | 15 | 2,761 | 2,641 | 1.02% | 105 | 26 | Township |
| Jefferson | 16 | 2,143 | 2,054 | 0.99% | 59 | 37 | Township |
| Woodburn | 17 | 1,627 | 1,556 | 0.87% | 1,690 | 1 | City |
| Harlan | 18 | 1,608 | 1,715 | -0.12% | 462 | 3 | CDP |
| Monroeville | 19 | 1,354 | 1,297 | 0.82% | 1,727 | 1 | Town |
| Grabill | 20 | 1,173 | 1,117 | 0.95% | 1,802 | 1 | Town |
| Hoagland | 21 | 892 | 908 | 0.45% | 263 | 3 | CDP |
| Zanesville | 22 | 596 | 579 | 0.51% | 721 | 1 | Town |
| Jackson | 23 | 526 | 505 | 0.77% | 21 | 25 | Township |
Fort Wayne is the largest city in Allen County, with a population of 275,405.
Jackson is the smallest city in Allen County, with a population of 526.
There are 23 cities in Allen County, Indiana.