9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Wapello | 1 | 1,998 | 2,081 | -0.7% | 1,538 | 1 | City |
| Columbus Junction | 2 | 1,773 | 1,836 | -0.56% | 826 | 2 | City |
| Morning Sun | 3 | 677 | 752 | -1.74% | 871 | 1 | City |
| Grandview | 4 | 426 | 441 | -0.47% | 1,868 | 0 | City |
| Columbus City | 5 | 383 | 389 | -0.26% | 1,596 | 0 | City |
| Letts | 6 | 356 | 362 | -0.28% | 628 | 1 | City |
| Fredonia | 7 | 225 | 230 | -0.44% | 1,490 | 0 | City |
| Oakville | 8 | 197 | 199 | 0% | 472 | 0 | City |
| Cotter | 9 | 39 | 41 | 0% | 398 | 0 | City |
Wapello is the largest city in Louisa County, with a population of 1,998.
Cotter is the smallest city in Louisa County, with a population of 39.
There are 9 cities in Louisa County, Iowa.