7 cities
| City | County | 2025 Pop. ↓ |
|---|---|---|
| Inverness | Arapahoe County | 3,082 |
| Idaho Springs | Clear Creek County | 1,674 |
| Indian Hills | Jefferson County | 1,486 |
| Ignacio | La Plata County | 846 |
| Idledale | Jefferson County | 348 |
| Iliff | Logan County | 239 |
| Idalia | Yuma County | 96 |