12 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Northglenn | Adams County | 38,348 |
| New Castle | Garfield County | 4,889 |
| Niwot | Boulder County | 4,112 |
| Nederland | Boulder County | 1,491 |
| Nucla | Montrose County | 590 |
| Nunn | Weld County | 540 |
| Norwood | San Miguel County | 520 |
| Naturita | Montrose County | 480 |
| North La Junta | Bent County | 448 |
| No Name | Garfield County | 306 |
| Nathrop | Chaffee County | 185 |
| North Washington | Adams County | 169 |