6 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waukon | 1 | 3,788 | 3,820 | -0.13% | 1,334 | 3 | City |
| Postville | 2 | 2,374 | 2,506 | -0.92% | 1,146 | 2 | City |
| Lansing | 3 | 958 | 961 | 0% | 889 | 1 | City |
| New Albin | 4 | 435 | 435 | 0% | 1,726 | 0 | City |
| Harpers Ferry | 5 | 279 | 261 | 1.09% | 439 | 1 | City |
| Waterville | 6 | 114 | 108 | 0.88% | 322 | 0 | City |
Waukon is the largest city in Allamakee County, with a population of 3,788.
Waterville is the smallest city in Allamakee County, with a population of 114.
There are 6 cities in Allamakee County, Iowa.