307
Area code
WY
United States geographic area code, in service since 1947-01-01.
Statusin service
Introduced1947-01-01
JurisdictionWY, US
Local dialing7D
Time zoneMountain
Last verified2026-09-17
Utilization 66.3% of assignable prefixes assigned
As of 09/17/2026
0%525 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 2001-01-29, most recent 2026-09-11.
Area codes serve rate-center geographies, not municipal boundaries. “WY” 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 | 83 | 15.8% |
| 02 | UNION TELEPHONE COMPANY | 65 | 12.4% |
| 03 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - WY | 60 | 11.4% |
| 04 | NEW CINGULAR WIRELESS PCS, LLC | 49 | 9.3% |
| 05 | ONVOY, LLC - WY | 40 | 7.6% |
| 06 | LEVEL 3 COMMUNICATIONS, LLC - WY | 27 | 5.1% |
| 07 | BANDWIDTH.COM CLEC, LLC - WY | 19 | 3.6% |
| 08 | RT COMMUNICATIONS | 17 | 3.2% |
| 09 | 17 | 3.2% | |
| 10 | T-MOBILE USA, INC. | 14 | 2.7% |
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- 1947-01-01Area code 307 entered service.