| District of Colorado area codes: 303 | |
|---|---|
| Country | United States |
| State/Province | Colorado |
| Major City | Denver |
| Time Zone | Mountain (UTC-07:00) |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 303-200 | Arapahoe | Denver, CO | Teleport Communications America |
| 303-201 | Jefferson | Denver, CO | Usa Mobility Wireless |
| 303-202 | Jefferson | Denver, CO | Qwest Corporation |
| 303-203 | Jefferson | Denver, CO | American Messaging (am) |
| 303-204 | Jefferson | Denver, CO | Cellco Partnership DBA Verizon Wireless |
| 303-205 | Jefferson | Denver, CO | Qwest Corporation |
| 303-206 | Jefferson | Denver, CO | Usa Mobility Wireless |
| 303-207 | Jefferson | Denver, CO | Usa Mobility Wireless |
| 303-208 | Jefferson | Denver, CO | Usa Mobility Wireless |
| 303-209 | Denver | Denver, CO | Mcimetro Access Transmission Services LLC |
| 303-210 | Jefferson | Denver, CO | Sprint Spectrum L.p. |
| 303-212 | Jefferson | Denver, CO | Contact Paging Of Colorado |
| 303-213 | Jefferson | Denver, CO | Usa Mobility Wireless |
| 303-214 | Denver | Aurora, CO | Mcimetro Access Transmission Services LLC |
| 303-215 | Jefferson | Golden, CO | Qwest Corporation |
| 303-216 | Jefferson | Golden, CO | Qwest Corporation |
| 303-217 | Denver | Denver, CO | Mcimetro Access Transmission Services LLC |
| 303-218 | Denver | Denver, CO | Mcimetro Access Transmission Services LLC |
| 303-219 | Adams | Brighton, CO | Mcimetro Access Transmission Services LLC |
| 303-220 | Denver | Denver, CO | Qwest Corporation |
There are 783 prefixes, In the code area, the major cities are Arvada, CO;Aurora, CO;Boulder, CO;Brighton, CO;Bro. The major city is Denver.