970
Area code
CO
United States geographic area code, in service since 1995-04-02. Part of the 748/970 overlay complex — ten-digit dialing required.
Statusin service
Introduced1995-04-02
JurisdictionCO, US
Local dialing10D
Time zoneMountain
Last verified2026-09-17
Utilization 99.6% of assignable prefixes assigned
As of 09/17/2026
0%789 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 2001-01-16, most recent 2026-09-10.
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 | QWEST CORPORATION | 189 | 24% |
| 02 | ONVOY, LLC - CO | 88 | 11.2% |
| 03 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CO | 77 | 9.8% |
| 04 | T-MOBILE USA, INC. | 70 | 8.9% |
| 05 | NEW CINGULAR WIRELESS PCS, LLC | 54 | 6.8% |
| 06 | LEVEL 3 COMMUNICATIONS, LLC - CO | 47 | 6% |
| 07 | TON80 COMMUNICATIONS, LLC | 22 | 2.8% |
| 08 | CENTURYTEL OF EAGLE, INC. DBA CENTURYLINK | 21 | 2.7% |
| 09 | UNION TELEPHONE COMPANY | 17 | 2.2% |
| 10 | BANDWIDTH.COM CLEC, LLC - CO | 16 | 2% |
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- 2024-02-13 NPA 748 to Overlay NPA 970 (Colorado)
- 1995-04-02Area code 970 entered service (created from 303).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2024-02-13 | PL-625 ↗ | NPA 748 to Overlay NPA 970 (Colorado) |
| 2021-01-08 | PL-556 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Lifeline) – supersedes PL-544 |
| 2020-08-17 | PL-544 ↗ | Transition to 10-digit dialing (for 988 as 3-digit access to National Suicide Prevention Hotline |
| 1994-09-21 | IL-94-09-012 ↗ | NANP-SPLIT OF 303 (COLORADO) NUMBERING PLAN AREA (NPA) |