11 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lima | 1 | 34,293 | 35,483 | -0.57% | 2,518 | 14 | City |
| Delphos | 2 | 7,053 | 7,115 | -0.14% | 2,123 | 3 | City |
| Bluffton | 3 | 3,839 | 3,964 | -0.54% | 1,039 | 4 | Village |
| Spencerville | 4 | 2,145 | 2,202 | -0.42% | 2,223 | 1 | Village |
| Elida | 5 | 1,893 | 1,926 | -0.26% | 1,625 | 1 | Village |
| Cridersville | 6 | 1,719 | 1,796 | -0.75% | 1,433 | 1 | Village |
| Cairo | 7 | 503 | 518 | -0.4% | 1,816 | 0 | Village |
| McGuffey | 8 | 454 | 463 | -0.22% | 1,220 | 0 | Village |
| Harrod | 9 | 426 | 429 | 0% | 1,821 | 0 | Village |
| Lafayette | 10 | 392 | 401 | -0.25% | 1,682 | 0 | Village |
| Beaverdam | 11 | 310 | 321 | -0.64% | 492 | 1 | Village |
Lima is the largest city in Allen County, with a population of 34,293.
Beaverdam is the smallest city in Allen County, with a population of 310.
There are 11 cities in Allen County, Ohio.