9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Grundy Center | 1 | 2,806 | 2,805 | 0% | 1,092 | 2.57 | City |
| Reinbeck | 2 | 1,665 | 1,665 | 0% | 767 | 2.17 | City |
| Dike | 3 | 1,296 | 1,300 | -0.08% | 933 | 1.39 | City |
| Conrad | 4 | 1,097 | 1,092 | 0.09% | 893 | 1.23 | City |
| Wellsburg | 5 | 712 | 722 | -0.28% | 648 | 1.10 | City |
| Holland | 6 | 264 | 269 | -0.38% | 1,048 | 0.25 | City |
| Stout | 7 | 193 | 190 | 0.52% | 661 | 0.29 | City |
| Beaman | 8 | 158 | 160 | 0% | 845 | 0.19 | City |
| Morrison | 9 | 98 | 95 | 1.03% | 1,032 | 0.10 | City |
Grundy Center is the largest city in Grundy County, with a population of 2,806.
Morrison is the smallest city in Grundy County.
There are 9 cities in Grundy County, Iowa.