| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Fargo | 1 | 138,574 | 125,989 | 1.69% | 2,671 | 52 | City |
| West Fargo | 2 | 41,619 | 38,894 | 1.08% | 2,573 | 16 | City |
| Horace | 3 | 7,741 | 3,249 | 10.57% | 611 | 13 | City |
| Casselton | 4 | 2,484 | 2,478 | -0.04% | 1,149 | 2 | City |
| Mapleton | 5 | 1,528 | 1,332 | 2.14% | 391 | 4 | City |
| Kindred | 6 | 1,066 | 931 | 2.11% | 736 | 1 | City |
| Reile's Acres | 7 | 913 | 724 | 3.75% | 804 | 1 | City |
| Harwood | 8 | 854 | 796 | 1.07% | 655 | 1 | City |
| Argusville | 9 | 471 | 485 | -0.63% | 118 | 4 | City |
| Oxbow | 10 | 369 | 377 | -0.54% | 241 | 2 | City |
| Arthur | 11 | 327 | 326 | -0.3% | 214 | 2 | City |
| Hunter | 12 | 323 | 333 | -0.62% | 216 | 1 | City |
| Tower City | 13 | 274 | 266 | 0.37% | 134 | 2 | City |
| Davenport | 14 | 257 | 254 | -0.39% | 945 | 0 | City |
| Leonard | 15 | 239 | 247 | -0.83% | 318 | 1 | City |
| Grandin | 16 | 193 | 185 | 1.05% | 1,066 | 0 | City |
| Frontier | 17 | 192 | 197 | -0.52% | 1,021 | 0 | City |
| Buffalo | 18 | 186 | 194 | -1.06% | 387 | 0 | City |
| Page | 19 | 185 | 192 | -1.07% | 184 | 1 | City |
| Gardner | 20 | 124 | 128 | -0.8% | 249 | 0 | City |
| Amenia | 21 | 90 | 87 | 0% | 60 | 1 | City |
| North River | 22 | 55 | 57 | -1.79% | 902 | 0 | City |
| Prairie Rose | 23 | 54 | 56 | -1.82% | 1,317 | 0 | City |
| Briarwood | 24 | 51 | 53 | -1.92% | 357 | 0 | City |
| Ayr | 25 | 10 | 10 | 0% | 118 | 0 | City |
Fargo is the largest city in Cass County, with a population of 138,574.
Ayr is the smallest city in Cass County, with a population of 10.
There are 25 cities in Cass County, North Dakota.