25 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clear Lake | 1 | 1,196 | 1,219 | -0.42% | 348 | 3 | City |
| Norden | 2 | 294 | 286 | 0.34% | 5 | 54 | Township |
| Gary | 3 | 233 | 233 | 0% | 347 | 1 | City |
| Clear Lake | 4 | 232 | 228 | 0% | 6 | 37 | Township |
| Scandinavia | 5 | 223 | 218 | 0% | 4 | 55 | Township |
| Clear Lake | 6 | 211 | 219 | -0.47% | 6 | 35 | Township |
| Havana | 7 | 200 | 196 | 0% | 5 | 42 | Township |
| Goodwin | 8 | 196 | 192 | 0% | 5 | 40 | Township |
| Toronto | 9 | 194 | 198 | -0.51% | 632 | 0 | Town |
| Goodwin | 10 | 151 | 146 | 0.67% | 319 | 0 | Town |
| Brandt | 11 | 142 | 138 | 0.71% | 4 | 36 | Township |
| Grange | 12 | 141 | 137 | 0.71% | 4 | 36 | Township |
| Astoria | 13 | 129 | 134 | -0.77% | 822 | 0 | Town |
| Brandt | 14 | 119 | 116 | 0% | 94 | 1 | Town |
| Altamont | 15 | 112 | 108 | 0.9% | 3 | 37 | Township |
| Lowe | 16 | 110 | 106 | 0.92% | 3 | 36 | Township |
| Glenwood | 17 | 108 | 108 | -0.92% | 3 | 43 | Township |
| Blom | 18 | 102 | 98 | 0.99% | 3 | 36 | Township |
| Hidewood | 19 | 100 | 96 | 1.01% | 3 | 36 | Township |
| Rome | 20 | 79 | 77 | 0% | 2 | 32 | Township |
| Portland | 21 | 62 | 60 | 1.64% | 2 | 35 | Township |
| Altamont | 22 | 33 | 32 | 0% | 26 | 1 | Town |
| Antelope Valley | 23 | 27 | 27 | 0% | 1 | 19 | Township |
| Clear Lake | 24 | 23 | 23 | 0% | 1 | 34 | Township |
| Albee | 25 | 8 | 8 | 0% | 61 | 0 | Town |
Clear Lake is the largest city in Deuel County, with a population of 1,196.
Albee is the smallest city in Deuel County, with a population of 8.
There are 25 cities in Deuel County, South Dakota.