| District of Colorado area codes: 720 | |
|---|---|
| Country | United States |
| State/Province | Colorado |
| Major City | Denver |
| Time Zone | Mountain |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 720-221 | Jefferson | Denver, CO | Xo Colorado |
| 720-222 | Arapahoe | Englewood, CO | Xo Colorado |
| 720-223 | Adams | Brighton, CO | Xo Colorado |
| 720-224 | Jefferson | Denver, CO | Xo Colorado |
| 720-225 | Jefferson | Denver, CO | Xo Colorado |
| 720-226 | Jefferson | Denver, CO | Xo Colorado |
| 720-227 | Jefferson | Denver, CO | Xo Colorado |
| 720-228 | Jefferson | Denver, CO | Xo Colorado |
| 720-229 | Jefferson | Denver, CO | Xo Colorado |
| 720-230 | Adams | Brighton, CO | Xo Colorado |
| 720-231 | Jefferson | Denver, CO | T-mobile Usa |
| 720-232 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-233 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-234 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-235 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-236 | Denver | Denver, CO | Sprint Spectrum L.p. |
| 720-237 | Jefferson | Denver, CO | New Cingular Wireless PCS |
| 720-238 | Denver | Denver, CO | T-mobile Usa |
| 720-239 | Denver | Denver, CO | AT&T Local |
| 720-240 | Jefferson | Denver, CO | Xo Colorado |
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.