MI
United States geographic area code, in service since 1947-01-01. Part of the 313/679 overlay complex — ten-digit dialing required.
Split from 313. Created 313. Created 810. Created 734. Created 679. Overlaid with 679 .
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-03-09, most recent 2026-05-27.
Area codes serve rate-center geographies, not municipal boundaries. “MI” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | MICHIGAN BELL TEL CO | 244 | 31.2% |
| 02 | OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC | 141 | 18% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC - IL | 95 | 12.1% |
| 04 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MI | 54 | 6.9% |
| 05 | BANDWIDTH.COM CLEC, LLC - MI | 28 | 3.6% |
| 06 | ONVOY, LLCV - MI | 25 | 3.2% |
| 07 | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - MI | 25 | 3.2% |
| 08 | AMERICAN MESSAGING SERVICES, LLC | 24 | 3.1% |
| 09 | LEVEL 3 COMMUNICATIONS, LLC - MI | 22 | 2.8% |
| 10 | TELEPORT COMMUNICATIONS AMERICA, LLC - MI | 18 | 2.3% |
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- 2023-07-13 NPA 679 to Overlay NPA 313 (Michigan)
- 1947-01-01Area code 313 entered service (created from 313).
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2023-07-13 | PL-618 ↗ | NPA 679 to Overlay NPA 313 (Michigan) |
| 1997-05-30 | PL-066 ↗ | NANP-Split of 313 (Michigan) Numbering Plan Area (NPA) |
| 1992-11-23 | IL-92-11-022 ↗ | NANP-SPLIT OF 313 (MICHIGAN) NUMBERING PLAN AREA (NPA) |
| 1989-12-13 | IL-89-12-022 ↗ | NANP - INTERCHANGEABLE CENTRAL OFFICE CODES IN THE MICHIGAN 313 NPA |