14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Humboldt | 1 | 4,679 | 4,788 | -0.47% | 1,006 | 4.65 | City |
| Dakota City | 2 | 754 | 759 | -0.13% | 1,033 | 0.73 | City |
| Gilmore City | 3 | 474 | 484 | -0.42% | 383 | 1.24 | City |
| Livermore | 4 | 371 | 381 | -0.54% | 570 | 0.65 | City |
| Bode | 5 | 297 | 306 | -0.67% | 735 | 0.40 | City |
| Renwick | 6 | 225 | 232 | -0.44% | 225 | 1 | City |
| Thor | 7 | 175 | 179 | -0.57% | 176 | 0.99 | City |
| Rutland | 8 | 115 | 117 | 0% | 128 | 0.90 | City |
| St. Joseph | 9 | 84 | 122 | 7.69% | 97 | 0.86 | CDP |
| Bradgate | 10 | 73 | 75 | 0% | 140 | 0.52 | City |
| Irvington | 11 | 68 | 41 | 7.94% | 67 | 1.01 | CDP |
| Hardy | 12 | 52 | 54 | 0% | 116 | 0.45 | City |
| Ottosen | 13 | 41 | 41 | 0% | 84 | 0.49 | City |
| Rodman | 14 | 28 | 30 | 0% | 192 | 0.15 | City |
Humboldt is the largest city in Humboldt County, with a population of 4,679.
Rodman is the smallest city in Humboldt County.
There are 14 cities in Humboldt County, Iowa.