21 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Estelline | 1 | 780 | 744 | 0.78% | 825 | 1 | City |
| Castlewood | 2 | 724 | 700 | 0.56% | 630 | 1 | City |
| Norden | 3 | 720 | 638 | 2.13% | 19 | 39 | Township |
| Lake Norden | 4 | 657 | 560 | 2.5% | 753 | 1 | City |
| Bryant | 5 | 483 | 470 | 0.42% | 922 | 1 | City |
| Hayti | 6 | 460 | 382 | 2.91% | 1,041 | 0 | Town |
| Estelline | 7 | 346 | 305 | 2.37% | 7 | 47 | Township |
| Bryant | 8 | 346 | 341 | 0.29% | 16 | 21 | Township |
| Oxford | 9 | 341 | 297 | 3.02% | 7 | 52 | Township |
| Hayti | 10 | 308 | 268 | 2.67% | 10 | 32 | Township |
| Cleveland | 11 | 307 | 276 | 1.32% | 9 | 35 | Township |
| Castlewood | 12 | 271 | 238 | 2.26% | 8 | 35 | Township |
| Hamlin | 13 | 268 | 243 | 1.13% | 7 | 36 | Township |
| Dempster | 14 | 251 | 223 | 1.62% | 7 | 36 | Township |
| Opdahl | 15 | 218 | 193 | 1.87% | 6 | 34 | Township |
| Brantford | 16 | 155 | 138 | 1.97% | 3 | 53 | Township |
| Garfield | 17 | 140 | 121 | 2.94% | 4 | 35 | Township |
| Dixon | 18 | 134 | 117 | 3.08% | 4 | 36 | Township |
| Hazel | 19 | 97 | 99 | 0% | 401 | 0 | Town |
| Bryant | 20 | 27 | 27 | 0% | 1 | 35 | Township |
| Bryant | 21 | 17 | 17 | 0% | 0.00 | 35 | Township |
Estelline is the largest city in Hamlin County, with a population of 780.
Bryant is the smallest city in Hamlin County, with a population of 17.
There are 21 cities in Hamlin County, South Dakota.