| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Estelline | 1 | 802 | 745 | 1.26% | 849 | 1 | City |
| Castlewood | 2 | 746 | 700 | 0.95% | 649 | 1 | City |
| Lake Norden | 3 | 670 | 560 | 2.92% | 768 | 1 | City |
| Hayti | 4 | 497 | 383 | 3.11% | 1,124 | 0 | Town |
| Bryant | 5 | 492 | 468 | 0.82% | 939 | 1 | City |
| Hazel | 6 | 105 | 103 | 0% | 434 | 0 | Town |
Estelline is the largest city in Hamlin County, with a population of 802.
Hazel is the smallest city in Hamlin County, with a population of 105.
There are 6 cities in Hamlin County, South Dakota.