303 area code is a telephone area code in the North American Numbering Plan (NANP) for the Denver metropolitan area and several surrounding suburbs in Colorado, United States. The area code was one of the original area codes created in 1947.
| Area Code | 303 |
|---|---|
| Major City | Denver |
| Service Date | 01/01/1947 |
| Time Zone | Mountain |
| Overlay Complex | 303/720/983 |
| Location | Colorado (CO) |
| Country | United States |
Some of the cities served by area code 303 include Wilmington, Dover, Newark, Bear, Middletown, Brookside, Glasgow, Hockessin, Pike Creek Valley and more.
| Area code | City/Town | County |
|---|---|---|
| 303 | Allenspark | Boulder |
| 303 | Arvada | Jefferson |
| 303 | Aurora | Adams |
| 303 | Bailey | Park |
| 303 | Bennett | Adams |
| 303 | Black Hawk | Gilpin |
| 303 | Bond | Eagle |
| 303 | Boulder | Boulder |
| 303 | Brighton | Adams |
| 303 | Broomfield | Broomfield |
| 303 | Buffalo Creek | Jefferson |
| 303 | Byers | Arapahoe |
| 303 | Castle Rock | Douglas |
| 303 | Central City | Gilpin |
| 303 | Commerce City | Adams |
| 303 | Conifer | Jefferson |
| 303 | Dacono | Weld |
| 303 | Deer Trail | Arapahoe |
| 303 | Denver | Adams |
| 303 | Dumont | Clear Creek |
| 303 | Dupont | Adams |
| 303 | Eastlake | Adams |
| 303 | Elbert | El Paso |
| 303 | Eldorado Springs | Boulder |
| 303 | Elizabeth | Elbert |
| 303 | Empire | Clear Creek |
| 303 | Englewood | Arapahoe |
| 303 | Erie | Weld |
| 303 | Evergreen | Jefferson |
| 303 | Firestone | Weld |
| 303 | Fort Lupton | Weld |
| 303 | Franktown | Douglas |
| 303 | Frederick | Weld |
| 303 | Georgetown | Clear Creek |
| 303 | Golden | Jefferson |
| 303 | Grant | Park |
| 303 | Henderson | Adams |
| 303 | Hereford | Weld |
| 303 | Highlands Ranch | Douglas |
| 303 | Hudson | Weld |
| 303 | Hygiene | Boulder |
| 303 | Idaho Springs | Clear Creek |
| 303 | Idledale | Jefferson |
| 303 | Indian Hills | Jefferson |
| 303 | Jamestown | Boulder |
| 303 | Keenesburg | Weld |
| 303 | Kiowa | Elbert |
| 303 | Kittredge | Jefferson |
| 303 | Lafayette | Boulder |
| 303 | Lakewood | Jefferson |
| 303 | Larkspur | Douglas |
| 303 | Littleton | Arapahoe |
| 303 | Longmont | Boulder |
| 303 | Louisville | Boulder |
| 303 | Louviers | Douglas |
| 303 | Lyons | Boulder |
| 303 | Morrison | Jefferson |
| 303 | Nederland | Boulder |
| 303 | Niwot | Boulder |
| 303 | Parker | Douglas |
| 303 | Pine | Jefferson |
| 303 | Pinecliffe | Boulder |
| 303 | Roggen | Weld |
| 303 | Rollinsville | Gilpin |
| 303 | Sedalia | Douglas |
| 303 | Sedgwick | Sedgwick |
| 303 | Shawnee | Park |
| 303 | Silver Plume | Clear Creek |
| 303 | Strasburg | Adams |
| 303 | Thornton | Adams |
| 303 | Ward | Boulder |
| 303 | Watkins | Adams |
| 303 | Westminster | Adams |
| 303 | Wheat Ridge | Jefferson |