Area code 231
Area code 231 is a telephone area code in the North American Numbering Plan (NANP) for the northwestern portion of the Lower Peninsula in the U.S. state of Michigan.
History
[edit]Area code 231 was created in June 1999 by an area code split of area code 616, which had served the entire western half of the Lower Peninsula, extending west from the north-south line aligned with the Mackinac Bridge. 231 was carved out of the northern part. It is centered around the western half of the territory generally defined as Northern Michigan. It also includes Muskegon, which is almost universally counted as part of West Michigan.
Service area
[edit]The numbering plan area includes the following communities:
Area code 231 also serves Bois Blanc Township, which is in the Upper Peninsula, and is the only municipality there using 231, while the rest uses 906.
External links
[edit]- Planning letter 167, which details 231's creation (PDF)
- "Michigan [map] | NANPA". NANPA. Retrieved 2025-06-25.
- Map of Michigan area codes Archived 2008-06-30 at the Wayback Machine at North American Numbering Plan Administration's website
- List of exchanges from AreaCodeDownload.com, 231 Area Code
| North: 906 | ||
| West: Lake Michigan | 231 | East: 989 |
| South: 616 |
44°30′N 85°30′W / 44.5°N 85.5°W
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