| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waterloo | 1 | 66,855 | 67,259 | -0.1% | 1,085 | 62 | City |
| Cedar Falls | 2 | 41,364 | 40,700 | 0.3% | 1,405 | 29 | City |
| Evansdale | 3 | 4,443 | 4,557 | -0.45% | 1,112 | 4 | City |
| Hudson | 4 | 3,114 | 2,544 | 2.84% | 369 | 8 | City |
| La Porte City | 5 | 2,230 | 2,278 | -0.36% | 872 | 3 | City |
| Elk Run Heights | 6 | 1,050 | 1,067 | -0.28% | 969 | 1 | City |
| Dunkerton | 7 | 833 | 840 | -0.24% | 696 | 1 | City |
| Gilbertville | 8 | 787 | 785 | 0.13% | 2,198 | 0 | City |
| Raymond | 9 | 745 | 759 | -0.4% | 456 | 2 | City |
Waterloo is the largest city in Black Hawk County, with a population of 66,855.
Raymond is the smallest city in Black Hawk County, with a population of 745.
There are 9 cities in Black Hawk County, Iowa.