720
Area code
CO
United States geographic area code, in service since 1998-06-01. Part of the 303/720/983 overlay complex — ten-digit dialing required.
Statusin service
Introduced1998-06-01
JurisdictionCO, US
Local dialing10D
Time zoneMountain
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-01-12, most recent 2024-09-03.
Area codes serve rate-center geographies, not municipal boundaries. “CO” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | T-MOBILE USA, INC. | 132 | 16.5% |
| 02 | QWEST CORPORATION | 103 | 12.9% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC | 92 | 11.5% |
| 04 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO | 75 | 9.4% |
| 05 | BANDWIDTH.COM CLEC, LLC - CO | 55 | 6.9% |
| 06 | ONVOY, LLC - CO | 54 | 6.8% |
| 07 | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 51 | 6.4% |
| 08 | LEVEL 3 COMMUNICATIONS, LLC - CO | 46 | 5.8% |
| 09 | TELEPORT COMMUNICATIONS AMERICA, LLC - CO | 31 | 3.9% |
| 10 | COMCAST IP PHONE, LLC | 21 | 2.6% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 1998-06-01Area code 720 entered service (created from 303).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2021-07-29 | PL-563 ↗ | NPA 983 to Overlay NPA 303/720 (Colorado) |
| 1998-03-24 | PL-117 ↗ | NANP-Overlay of 303 (Colorado) Numbering Plan Area (NPA) with 720 NPA |