| District of Colorado area codes: 720 | |
|---|---|
| Country | United States |
| State/Province | Colorado |
| Major City | Denver |
| Time Zone | Mountain |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 720-301 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 720-302 | Arapahoe | Denver, CO | Teleport Communications America |
| 720-304 | Jefferson | Denver, CO | Qwest Corporation |
| 720-305 | Jefferson | Denver, CO | Tw Telecom Of Colorado LLC |
| 720-306 | Denver | Denver, CO | Eschelon Telecom Of Colorado |
| 720-307 | Larimer | Lyons, CO | AT&T Local |
| 720-308 | Jefferson | Denver, CO | New Cingular Wireless PCS |
| 720-309 | Jefferson | Denver, CO | Leap Wireless Intl DBA Cricket Comm |
| 720-310 | Larimer | Lyons, CO | Teleport Communications America |
| 720-312 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 720-313 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 720-314 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 720-315 | Jefferson | Denver, CO | 360networks (usa) Inc. |
| 720-316 | Denver | Denver, CO | Bandwidth.com Clec |
| 720-317 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-318 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-319 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 720-320 | Jefferson | Denver, CO | New Cingular Wireless PCS |
| 720-321 | Jefferson | Denver, CO | Qwest Corporation |
| 720-322 | Denver | Denver, CO | Qwest Corporation |
There are 519 prefixes, In the code area, the major cities are Arvada, CO;Aurora, CO;Boulder, CO;Brighton, CO;Bro. The major city is Denver.