| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Humboldt | 1 | 4,658 | 4,788 | -0.36% | 1,001 | 5 | City |
| Dakota City | 2 | 746 | 759 | -0.13% | 1,022 | 1 | City |
| Gilmore City | 3 | 469 | 485 | -0.42% | 379 | 1 | City |
| Livermore | 4 | 373 | 382 | -0.27% | 573 | 1 | City |
| Bode | 5 | 296 | 306 | -0.67% | 733 | 0 | City |
| Renwick | 6 | 221 | 228 | -0.45% | 221 | 1 | City |
| Thor | 7 | 176 | 179 | -0.56% | 177 | 1 | City |
| Rutland | 8 | 114 | 117 | -0.87% | 127 | 1 | City |
| Bradgate | 9 | 72 | 75 | -1.37% | 138 | 1 | City |
| Hardy | 10 | 52 | 54 | -1.89% | 116 | 0 | City |
| Ottosen | 11 | 38 | 40 | -2.56% | 78 | 0 | City |
| Rodman | 12 | 28 | 30 | -3.45% | 192 | 0 | City |
Humboldt is the largest city in Humboldt County, with a population of 4,658.
Rodman is the smallest city in Humboldt County, with a population of 28.
There are 12 cities in Humboldt County, Iowa.