36 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Webster | 1 | 1,652 | 1,721 | -0.84% | 1,018 | 2 | City |
| Waubay | 2 | 523 | 515 | -0.38% | 11 | 46 | Township |
| Waubay | 3 | 474 | 474 | 0% | 326 | 1 | City |
| Webster | 4 | 297 | 293 | -0.34% | 9 | 33 | Township |
| Bristol | 5 | 272 | 285 | -1.09% | 521 | 1 | City |
| Kosciusko | 6 | 181 | 179 | -0.55% | 5 | 40 | Township |
| Roslyn | 7 | 179 | 183 | -0.56% | 821 | 0 | Town |
| Rusk | 8 | 125 | 123 | 0% | 4 | 35 | Township |
| Pierpont | 9 | 119 | 126 | -1.65% | 783 | 0 | Town |
| Andover | 10 | 116 | 111 | 0.87% | 2 | 71 | Township |
| Racine | 11 | 97 | 96 | -1.02% | 3 | 28 | Township |
| Central Point | 12 | 81 | 81 | -1.22% | 2 | 34 | Township |
| Grenville | 13 | 81 | 80 | 0% | 2 | 34 | Township |
| Wheatland | 14 | 81 | 77 | 2.53% | 2 | 36 | Township |
| Nutley | 15 | 78 | 78 | -1.27% | 2 | 34 | Township |
| Raritan | 16 | 78 | 74 | 2.63% | 2 | 35 | Township |
| Morton | 17 | 75 | 71 | 1.35% | 2 | 36 | Township |
| Union | 18 | 72 | 73 | -1.37% | 2 | 36 | Township |
| Liberty | 19 | 70 | 71 | -1.41% | 2 | 30 | Township |
| Andover | 20 | 68 | 67 | 0% | 252 | 0 | Town |
| Highland | 21 | 65 | 65 | -1.52% | 2 | 35 | Township |
| Kidder | 22 | 61 | 62 | -1.61% | 2 | 35 | Township |
| Egeland | 23 | 59 | 57 | 1.72% | 1 | 42 | Township |
| Bristol | 24 | 56 | 57 | -1.75% | 2 | 34 | Township |
| Independence | 25 | 55 | 56 | -1.79% | 2 | 34 | Township |
| Homer | 26 | 45 | 46 | -2.17% | 1 | 36 | Township |
| Grenville | 27 | 45 | 44 | 0% | 190 | 0 | Town |
| Valley | 28 | 44 | 43 | 0% | 1 | 36 | Township |
| York | 29 | 43 | 41 | 2.38% | 1 | 35 | Township |
| Butler | 30 | 35 | 36 | -2.78% | 1 | 35 | Township |
| Bristol | 31 | 33 | 33 | 0% | 1 | 36 | Township |
| Troy | 32 | 33 | 32 | 0% | 1 | 34 | Township |
| Lynn | 33 | 28 | 29 | -3.45% | 1 | 35 | Township |
| Farmington | 34 | 26 | 27 | -3.7% | 1 | 35 | Township |
| Oak Gulch | 35 | 24 | 23 | 0% | 1 | 35 | Township |
| Butler | 36 | 6 | 6 | 0% | 21 | 0 | Town |
Webster is the largest city in Day County, with a population of 1,652.
Butler is the smallest city in Day County, with a population of 6.
There are 36 cities in Day County, South Dakota.