10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iola | 1 | 5,264 | 5,398 | -0.42% | 1,134 | 5 | City |
| Humboldt | 2 | 1,802 | 1,847 | -0.39% | 1,180 | 2 | City |
| La Harpe | 3 | 489 | 485 | 0.2% | 614 | 1 | City |
| Gas | 4 | 463 | 471 | -0.22% | 643 | 1 | City |
| Moran | 5 | 461 | 467 | -0.22% | 1,100 | 0 | City |
| Savonburg | 6 | 76 | 75 | 0% | 396 | 0 | City |
| Earlton | 7 | 57 | 59 | 0% | 356 | 0 | City |
| Elsmore | 8 | 51 | 53 | 0% | 336 | 0 | City |
| Bassett | 9 | 22 | 22 | 0% | 328 | 0 | City |
| Lone Elm | 10 | 22 | 22 | 0% | 324 | 0 | City |
Iola is the largest city in Allen County, with a population of 5,264.
Lone Elm is the smallest city in Allen County, with a population of 22.
There are 10 cities in Allen County, Kansas.