| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Ottumwa | 1 | 25,320 | 25,462 | 0% | 1,576 | 16 | City |
| Eddyville | 2 | 959 | 967 | -0.1% | 835 | 1 | City |
| Eldon | 3 | 775 | 785 | -0.13% | 708 | 1 | City |
| Agency | 4 | 612 | 615 | 0% | 1,081 | 1 | City |
| Blakesburg | 5 | 262 | 267 | -0.38% | 967 | 0 | City |
| Kirkville | 6 | 160 | 155 | 0.63% | 284 | 1 | City |
| Chillicothe | 7 | 75 | 76 | 0% | 332 | 0 | City |
Ottumwa is the largest city in Wapello County, with a population of 25,320.
Chillicothe is the smallest city in Wapello County, with a population of 75.
There are 7 cities in Wapello County, Iowa.