City levels are determined by the county in which they are located. If the city is not named below, it may be located within a county listed below. Visit the National Association of Counties website and type the city name into the "City/Zip Search" tab to determine the city's county. If the city is not listed below or is not located in a county below, that city is a Level 1.
| Level | City | County |
|---|---|---|
| 4 | Aspen | Pitkin |
| 3 | Boulder / Broomfield | Boulder / Broomfield |
| 3 | Colorado Springs | El Paso |
| 3 | Cortez | Montezuma |
| 4 | Crested Butte / Gunnison | Gunnison |
| 4 | Denver / Aurora | Denver / Adams / Arapahoe / Jefferson |
| 3 | Douglas | Douglas |
| 4 | Durango | La Plata |
| 3 | Fort Collins / Loveland | Larimer |
| 4 | Grand Lake | Grand |
| 4 | Montrose | Montrose |
| 4 | Silverthorne / Breckenridge | Summit |
| 4 | Steamboat Springs | Routt |
| 4 | Telluride | San Miguel |
| 4 | Vail | Eagle |