6 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Estelline | 1 | 782 | 747 | 0.9% | 828 | 0.94 | City |
| Castlewood | 2 | 712 | 697 | 0.42% | 619 | 1.15 | City |
| Lake Norden | 3 | 624 | 558 | 2.13% | 716 | 0.87 | City |
| Bryant | 4 | 470 | 469 | 0% | 897 | 0.52 | City |
| Hayti | 5 | 428 | 392 | 1.66% | 968 | 0.44 | Town |
| Hazel | 6 | 101 | 103 | 0% | 417 | 0.24 | Town |
Estelline is the largest city in Hamlin County, with a population of 782.
Hazel is the smallest city in Hamlin County.
There are 6 cities in Hamlin County, South Dakota.