7 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waukon | 1 | 3,745 | 3,825 | -0.43% | 1,319 | 2.84 | City |
| Postville | 2 | 2,356 | 2,503 | -1.22% | 1,137 | 2.07 | City |
| Lansing | 3 | 948 | 962 | -0.32% | 879 | 1.08 | City |
| New Albin | 4 | 429 | 434 | -0.23% | 1,702 | 0.25 | City |
| Harpers Ferry | 5 | 276 | 261 | 1.1% | 434 | 0.64 | City |
| Burr Oak | 6 | 251 | 200 | 2.45% | 364 | 0.69 | CDP |
| Waterville | 7 | 112 | 109 | 0.9% | 316 | 0.35 | City |
Waukon is the largest city in Allamakee County, with a population of 3,745.
Waterville is the smallest city in Allamakee County.
There are 7 cities in Allamakee County, Iowa.