36 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Webster | 1 | 1,638 | 1,721 | -0.85% | 1,010 | 2 | City |
| Waubay | 2 | 521 | 515 | -0.38% | 11 | 46 | Township |
| Waubay | 3 | 474 | 474 | 0% | 326 | 1 | City |
| Webster | 4 | 296 | 293 | -0.34% | 9 | 33 | Township |
| Bristol | 5 | 270 | 285 | -0.74% | 517 | 1 | City |
| Kosciusko | 6 | 180 | 179 | -0.55% | 5 | 40 | Township |
| Roslyn | 7 | 178 | 183 | -0.56% | 817 | 0 | Town |
| Rusk | 8 | 125 | 123 | 0% | 4 | 35 | Township |
| Pierpont | 9 | 118 | 126 | -0.84% | 776 | 0 | Town |
| Andover | 10 | 117 | 111 | 0.86% | 2 | 71 | Township |
| Racine | 11 | 96 | 96 | -1.03% | 3 | 28 | Township |
| Wheatland | 12 | 83 | 77 | 2.47% | 2 | 36 | Township |
| Grenville | 13 | 81 | 80 | 0% | 2 | 34 | Township |
| Central Point | 14 | 80 | 81 | -1.23% | 2 | 34 | Township |
| Raritan | 15 | 80 | 74 | 2.56% | 2 | 35 | Township |
| Nutley | 16 | 77 | 78 | -1.28% | 2 | 34 | Township |
| Morton | 17 | 76 | 71 | 1.33% | 2 | 36 | Township |
| Union | 18 | 71 | 73 | -1.39% | 2 | 36 | Township |
| Liberty | 19 | 69 | 71 | -1.43% | 2 | 30 | Township |
| Andover | 20 | 68 | 67 | 0% | 252 | 0 | Town |
| Highland | 21 | 64 | 65 | -1.54% | 2 | 35 | Township |
| Egeland | 22 | 60 | 57 | 1.69% | 1 | 42 | Township |
| Kidder | 23 | 60 | 62 | -1.64% | 2 | 35 | Township |
| Bristol | 24 | 55 | 57 | -1.79% | 2 | 34 | Township |
| Independence | 25 | 54 | 56 | -1.82% | 2 | 34 | Township |
| Grenville | 26 | 45 | 44 | 0% | 190 | 0 | Town |
| Homer | 27 | 44 | 46 | -2.22% | 1 | 36 | Township |
| Valley | 28 | 44 | 43 | 0% | 1 | 36 | Township |
| York | 29 | 44 | 41 | 2.33% | 1 | 35 | Township |
| Butler | 30 | 34 | 36 | -2.86% | 1 | 35 | Township |
| Bristol | 31 | 33 | 33 | 0% | 1 | 36 | Township |
| Troy | 32 | 33 | 32 | 0% | 1 | 34 | Township |
| Lynn | 33 | 27 | 29 | -3.57% | 1 | 35 | Township |
| Farmington | 34 | 25 | 27 | -3.85% | 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 1,638.
Butler is the smallest city in Day County, with a population of 6.
There are 36 cities in Day County, South Dakota.