37 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Webster | 1 | 1,661 | 1,725 | -0.78% | 1,024 | 1.62 | City |
| Waubay township | 2 | 533 | 520 | 0.19% | 12 | 46.09 | Township |
| Waubay | 3 | 475 | 475 | 0% | 326 | 1.46 | City |
| Enemy Swim | 4 | 380 | 171 | 7.04% | 407 | 0.93 | CDP |
| Webster township | 5 | 305 | 293 | 0.99% | 9 | 33.34 | Township |
| Bristol | 6 | 277 | 289 | -0.72% | 531 | 0.52 | City |
| Kosciusko township | 7 | 184 | 178 | 0.55% | 5 | 39.60 | Township |
| Roslyn | 8 | 180 | 182 | 0% | 826 | 0.22 | Town |
| Pierpont | 9 | 122 | 126 | -0.81% | 803 | 0.15 | Town |
| Rusk township | 10 | 120 | 116 | 0% | 3 | 35.24 | Township |
| Andover township | 11 | 117 | 112 | 0.86% | 2 | 71.16 | Township |
| Racine township | 12 | 100 | 95 | 1.01% | 4 | 27.91 | Township |
| Nutley township | 13 | 83 | 79 | 1.22% | 2 | 34.02 | Township |
| Central Point township | 14 | 81 | 81 | -1.22% | 2 | 34.34 | Township |
| Grenville township | 15 | 76 | 75 | 0% | 2 | 33.55 | Township |
| Morton township | 16 | 76 | 72 | 1.33% | 2 | 35.52 | Township |
| Wheatland township | 17 | 76 | 78 | -1.3% | 2 | 36.19 | Township |
| Raritan township | 18 | 74 | 76 | -1.33% | 2 | 34.69 | Township |
| Liberty township | 19 | 70 | 71 | -1.41% | 2 | 30.09 | Township |
| Highland township | 20 | 69 | 65 | 1.47% | 2 | 35.39 | Township |
| Andover | 21 | 68 | 68 | 0% | 252 | 0.27 | Town |
| Union township | 22 | 66 | 70 | -2.94% | 2 | 35.59 | Township |
| Kidder township | 23 | 63 | 62 | 0% | 2 | 34.86 | Township |
| Egeland township | 24 | 62 | 58 | 1.64% | 1 | 41.51 | Township |
| Independence township | 25 | 59 | 55 | 1.72% | 2 | 33.98 | Township |
| Bristol township | 26 | 58 | 57 | 0% | 2 | 34.41 | Township |
| Homer township | 27 | 48 | 47 | 0% | 1 | 35.92 | Township |
| Grenville | 28 | 46 | 46 | 0% | 194 | 0.24 | Town |
| Valley township | 29 | 45 | 42 | 2.27% | 1 | 35.67 | Township |
| Butler township | 30 | 42 | 39 | 2.44% | 1 | 34.87 | Township |
| York township | 31 | 37 | 39 | -2.63% | 1 | 34.57 | Township |
| Troy township | 32 | 35 | 32 | 2.94% | 1 | 33.90 | Township |
| Bristol township | 33 | 34 | 34 | 0% | 1 | 35.67 | Township |
| Lynn township | 34 | 34 | 31 | 3.03% | 1 | 35.29 | Township |
| Farmington township | 35 | 30 | 27 | 3.45% | 1 | 35.49 | Township |
| Oak Gulch township | 36 | 26 | 23 | 4% | 1 | 34.58 | Township |
| Butler | 37 | 6 | 6 | 0% | 21 | 0.29 | Town |
Webster is the largest city in Day County, with a population of 1,661.
Butler is the smallest city in Day County.
There are 37 cities in Day County, South Dakota.