24 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Watertown | 1 | 23,896 | 22,683 | 0.85% | 1,296 | 18 | City |
| Pelican | 2 | 778 | 742 | 0.91% | 26 | 30 | Township |
| Lake | 3 | 683 | 657 | 1.04% | 33 | 21 | Township |
| Sheridan | 4 | 498 | 481 | 0.81% | 16 | 32 | Township |
| Elmira | 5 | 447 | 439 | 0.45% | 15 | 29 | Township |
| Florence | 6 | 333 | 332 | 0% | 481 | 1 | Town |
| Kranzburg | 7 | 328 | 313 | 0.92% | 5 | 61 | Township |
| Kampeska | 8 | 318 | 311 | 0.32% | 9 | 35 | Township |
| Fuller | 9 | 313 | 297 | 1.29% | 6 | 54 | Township |
| Rauville | 10 | 291 | 284 | 0.34% | 6 | 50 | Township |
| Henry | 11 | 271 | 255 | 1.12% | 187 | 1 | Town |
| Dexter | 12 | 213 | 207 | 0.47% | 4 | 60 | Township |
| Waverly | 13 | 204 | 193 | 1.49% | 4 | 45 | Township |
| South Shore | 14 | 190 | 189 | 0% | 136 | 1 | Town |
| Florence | 15 | 169 | 149 | 1.81% | 5 | 34 | Township |
| Kranzburg | 16 | 167 | 163 | 0.6% | 219 | 1 | Town |
| Germantown | 17 | 166 | 163 | 0% | 4 | 47 | Township |
| Richland | 18 | 157 | 148 | 1.95% | 5 | 34 | Township |
| Henry | 19 | 119 | 122 | -0.83% | 3 | 36 | Township |
| Graceland | 20 | 95 | 91 | 1.06% | 3 | 33 | Township |
| Henry | 21 | 94 | 93 | 0% | 3 | 34 | Township |
| Wallace | 22 | 94 | 93 | 0% | 707 | 0 | Town |
| Phipps | 23 | 64 | 62 | 0% | 2 | 33 | Township |
| Florence | 24 | 27 | 30 | -3.57% | 1 | 36 | Township |
Watertown is the largest city in Codington County, with a population of 23,896.
Florence is the smallest city in Codington County, with a population of 27.
There are 24 cities in Codington County, South Dakota.