44 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Iola | 1 | 5,286 | 5,396 | -0.43% | 1,184 | 4 | City |
| Iola | 2 | 5,286 | 5,398 | -0.43% | 1,184 | 4 | City |
| Humboldt | 3 | 1,809 | 1,846 | -0.44% | 1,185 | 2 | City |
| Humboldt | 4 | 1,809 | 1,847 | -0.44% | 1,185 | 2 | City |
| Elm | 5 | 1,174 | 1,173 | -0.09% | 25 | 47 | Township |
| Elm | 6 | 1,174 | 1,177 | -0.09% | 25 | 47 | Township |
| Iola | 7 | 785 | 783 | 0.13% | 18 | 43 | Township |
| Iola | 8 | 785 | 786 | 0.13% | 18 | 43 | Township |
| Marmaton | 9 | 746 | 754 | -0.53% | 13 | 56 | Township |
| Marmaton | 10 | 746 | 754 | -0.53% | 13 | 56 | Township |
| La Harpe | 11 | 488 | 484 | 0% | 612 | 1 | City |
| La Harpe | 12 | 488 | 485 | 0% | 612 | 1 | City |
| Gas | 13 | 464 | 470 | -0.43% | 644 | 1 | City |
| Gas | 14 | 464 | 471 | -0.43% | 644 | 1 | City |
| Moran | 15 | 462 | 467 | -0.22% | 1,103 | 0 | City |
| Moran | 16 | 462 | 467 | -0.22% | 1,103 | 0 | City |
| Elsmore | 17 | 354 | 353 | 0% | 6 | 64 | Township |
| Elsmore | 18 | 354 | 353 | 0% | 6 | 64 | Township |
| Carlyle | 19 | 290 | 288 | 0.35% | 10 | 30 | Township |
| Carlyle | 20 | 290 | 288 | 0.35% | 10 | 30 | Township |
| Humboldt | 21 | 269 | 271 | -0.37% | 11 | 25 | Township |
| Humboldt | 22 | 269 | 271 | -0.37% | 11 | 25 | Township |
| Osage | 23 | 263 | 261 | 0% | 5 | 48 | Township |
| Osage | 24 | 263 | 261 | 0% | 5 | 48 | Township |
| Salem | 25 | 248 | 246 | 0.4% | 5 | 48 | Township |
| Salem | 26 | 248 | 246 | 0.4% | 5 | 48 | Township |
| Cottage Grove | 27 | 223 | 221 | -0.45% | 6 | 37 | Township |
| Cottage Grove | 28 | 223 | 221 | -0.45% | 6 | 37 | Township |
| Geneva | 29 | 141 | 136 | 1.44% | 5 | 30 | Township |
| Geneva | 30 | 141 | 136 | 1.44% | 5 | 30 | Township |
| Deer Creek | 31 | 105 | 105 | -0.94% | 3 | 36 | Township |
| Deer Creek | 32 | 105 | 105 | -0.94% | 3 | 36 | Township |
| Savonburg | 33 | 76 | 75 | 0% | 396 | 0 | City |
| Savonburg | 34 | 76 | 75 | 0% | 396 | 0 | City |
| Earlton | 35 | 57 | 59 | -1.72% | 356 | 0 | City |
| Earlton | 36 | 57 | 59 | -1.72% | 356 | 0 | City |
| Elsmore | 37 | 51 | 53 | -1.92% | 336 | 0 | City |
| Elsmore | 38 | 51 | 53 | -1.92% | 336 | 0 | City |
| Urbana | 39 | 25 | 24 | 8.7% | 15 | 2 | CDP |
| Bassett | 40 | 22 | 22 | 0% | 328 | 0 | City |
| Bassett | 41 | 22 | 22 | 0% | 328 | 0 | City |
| Lone Elm | 42 | 22 | 22 | 0% | 324 | 0 | City |
| Lone Elm | 43 | 22 | 22 | 0% | 324 | 0 | City |
| Mildred | 44 | 15 | 23 | 7.14% | 22 | 1 | CDP |
Iola is the largest city in Allen County, with a population of 5,286.
Mildred is the smallest city in Allen County, with a population of 15.
There are 44 cities in Allen County, Kansas.