10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Parkersburg | 1 | 1,972 | 2,014 | -0.35% | 1,363 | 1 | City |
| Shell Rock | 2 | 1,263 | 1,268 | -0.08% | 788 | 2 | City |
| Clarksville | 3 | 1,227 | 1,260 | -0.41% | 937 | 1 | City |
| Aplington | 4 | 1,076 | 1,112 | -0.55% | 1,464 | 1 | City |
| Greene | 5 | 959 | 995 | -0.62% | 840 | 1 | City |
| Allison | 6 | 922 | 966 | -0.75% | 315 | 3 | City |
| Dumont | 7 | 603 | 636 | -0.82% | 345 | 2 | City |
| New Hartford | 8 | 546 | 572 | -0.73% | 881 | 1 | City |
| Bristow | 9 | 136 | 144 | -0.73% | 145 | 1 | City |
| Aredale | 10 | 58 | 60 | 0% | 58 | 1 | City |
Parkersburg is the largest city in Butler County, with a population of 1,972.
Aredale is the smallest city in Butler County, with a population of 58.
There are 10 cities in Butler County, Iowa.