| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Parkersburg | 1 | 1,960 | 2,017 | -0.46% | 1,355 | 1 | City |
| Shell Rock | 2 | 1,250 | 1,268 | -0.16% | 780 | 2 | City |
| Clarksville | 3 | 1,219 | 1,259 | -0.49% | 931 | 1 | City |
| Aplington | 4 | 1,078 | 1,111 | -0.55% | 1,467 | 1 | City |
| Greene | 5 | 927 | 995 | -1.28% | 812 | 1 | City |
| Allison | 6 | 925 | 964 | -0.86% | 316 | 3 | City |
| Dumont | 7 | 606 | 638 | -0.98% | 346 | 2 | City |
| New Hartford | 8 | 548 | 571 | -0.9% | 884 | 1 | City |
| Bristow | 9 | 133 | 142 | -1.48% | 142 | 1 | City |
| Aredale | 10 | 60 | 63 | -1.64% | 60 | 1 | City |
Parkersburg is the largest city in Butler County, with a population of 1,960.
Aredale is the smallest city in Butler County, with a population of 60.
There are 10 cities in Butler County, Iowa.