9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Grundy Center | 1 | 2,826 | 2,810 | 0.11% | 1,100 | 3 | City |
| Reinbeck | 2 | 1,674 | 1,671 | 0.06% | 771 | 2 | City |
| Dike | 3 | 1,290 | 1,299 | -0.08% | 929 | 1 | City |
| Conrad | 4 | 1,100 | 1,094 | 0.09% | 895 | 1 | City |
| Wellsburg | 5 | 704 | 718 | -0.28% | 641 | 1 | City |
| Holland | 6 | 259 | 264 | -0.38% | 1,028 | 0 | City |
| Stout | 7 | 194 | 193 | 0% | 664 | 0 | City |
| Beaman | 8 | 153 | 158 | -0.65% | 818 | 0 | City |
| Morrison | 9 | 102 | 99 | 0.99% | 1,074 | 0 | City |
Grundy Center is the largest city in Grundy County, with a population of 2,826.
Morrison is the smallest city in Grundy County, with a population of 102.
There are 9 cities in Grundy County, Iowa.