26 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clear Lake | 1 | 1,215 | 1,217 | 0% | 401 | 3.03 | City |
| Norden township | 2 | 293 | 284 | 0.34% | 5 | 54.02 | Township |
| Gary | 3 | 240 | 234 | 0.42% | 357 | 0.67 | City |
| Clear Lake township | 4 | 235 | 228 | 0.43% | 6 | 37.20 | Township |
| Scandinavia township | 5 | 226 | 218 | 0.44% | 4 | 54.59 | Township |
| Clear Lake township | 6 | 205 | 217 | -1.44% | 6 | 35.35 | Township |
| Goodwin township | 7 | 199 | 192 | 0.51% | 5 | 40.21 | Township |
| Havana township | 8 | 199 | 192 | 0.51% | 5 | 41.52 | Township |
| Toronto | 9 | 195 | 197 | 0% | 635 | 0.31 | Town |
| Goodwin | 10 | 150 | 147 | 0.67% | 316 | 0.47 | Town |
| Grange township | 11 | 142 | 141 | -0.7% | 4 | 35.94 | Township |
| Brandt township | 12 | 138 | 137 | -0.72% | 4 | 35.87 | Township |
| Astoria | 13 | 130 | 134 | -0.76% | 828 | 0.16 | Town |
| Clear Lake | 14 | 125 | 150 | 6.84% | 128 | 0.98 | CDP |
| Brandt | 15 | 120 | 115 | 0.84% | 95 | 1.26 | Town |
| Glenwood township | 16 | 115 | 108 | 1.77% | 3 | 42.79 | Township |
| Altamont township | 17 | 106 | 106 | -0.93% | 3 | 36.57 | Township |
| Lowe township | 18 | 106 | 106 | -0.93% | 3 | 35.73 | Township |
| Blom township | 19 | 102 | 98 | 0.99% | 3 | 35.77 | Township |
| Hidewood township | 20 | 95 | 95 | -1.04% | 3 | 35.84 | Township |
| Rome township | 21 | 82 | 78 | 1.23% | 3 | 32.14 | Township |
| Portland township | 22 | 69 | 62 | 2.99% | 2 | 35.27 | Township |
| Altamont | 23 | 31 | 31 | 0% | 25 | 1.25 | Town |
| Antelope Valley township | 24 | 26 | 26 | 0% | 1 | 19.18 | Township |
| Clear Lake township | 25 | 22 | 22 | 0% | 1 | 34.34 | Township |
| Albee | 26 | 9 | 9 | 0% | 69 | 0.13 | Town |
Clear Lake is the largest city in Deuel County, with a population of 1,215.
Albee is the smallest city in Deuel County.
There are 26 cities in Deuel County, South Dakota.