7 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waukon | 1 | 3,793 | 3,820 | -0.16% | 1,336 | 3 | City |
| Postville | 2 | 2,396 | 2,506 | -0.91% | 1,156 | 2 | City |
| Lansing | 3 | 958 | 961 | -0.1% | 889 | 1 | City |
| New Albin | 4 | 435 | 435 | 0% | 1,726 | 0 | City |
| Harpers Ferry | 5 | 276 | 261 | 1.1% | 434 | 1 | City |
| Burr Oak | 6 | 251 | 200 | 2.45% | 364 | 1 | CDP |
| Waterville | 7 | 113 | 108 | 0.89% | 319 | 0 | City |
Waukon is the largest city in Allamakee County, with a population of 3,793.
Waterville is the smallest city in Allamakee County, with a population of 113.
There are 7 cities in Allamakee County, Iowa.