10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Waterloo | 1 | 66,160 | 67,275 | -0.34% | 1,074 | 61.59 | City |
| Cedar Falls | 2 | 40,760 | 40,702 | 0.03% | 1,385 | 29.43 | City |
| Evansdale | 3 | 4,445 | 4,557 | -0.49% | 1,112 | 4 | City |
| Hudson | 4 | 2,924 | 2,543 | 2.67% | 346 | 8.45 | City |
| La Porte City | 5 | 2,243 | 2,283 | -0.36% | 877 | 2.56 | City |
| Elk Run Heights | 6 | 1,047 | 1,067 | -0.38% | 966 | 1.08 | City |
| Dunkerton | 7 | 827 | 839 | -0.24% | 691 | 1.20 | City |
| Gilbertville | 8 | 793 | 788 | 0.13% | 2,215 | 0.36 | City |
| Raymond | 9 | 741 | 758 | -0.4% | 453 | 1.64 | City |
| Washburn | 10 | 524 | 524 | -4.2% | 424 | 1.24 | CDP |
Waterloo is the largest city in Black Hawk County, with a population of 66,160.
Washburn is the smallest city in Black Hawk County.
There are 10 cities in Black Hawk County, Iowa.