12 cities
| City | County | 2026 Pop. ↓ |
|---|---|---|
| Northglenn | Adams County | 38,410 |
| New Castle | Garfield County | 4,885 |
| Niwot | Boulder County | 3,719 |
| Nederland | Boulder County | 1,495 |
| Nucla | Montrose County | 590 |
| Nunn | Weld County | 548 |
| Norwood | San Miguel County | 518 |
| North La Junta | Bent County | 512 |
| Naturita | Montrose County | 480 |
| No Name | Garfield County | 277 |
| North Washington | Adams County | 271 |
| Nathrop | Chaffee County | 137 |