231 area code — Muskegon, MI geographic
Phone numbers beginning 231 are registered to the Muskegon area of Michigan (Eastern time zone). The code entered service on June 5, 1999. Because of number portability and VoIP, the area code tells you where the number was issued, not where the caller is right now.
NANPA lists 571 active NXX prefixes in 231, assigned to 42 carriers. 381 of those prefixes are pooled — shared between carriers in thousands-number blocks. The code spans 99 rate centers (billing localities).
If a 231 call asks for money or personal data, treat the displayed number as unverified: hang up and reach the organization through its published number. Numbering data locates numbers, not callers.
Its parent code is 616, which it left in 1999.
Official projections put exhaust at 1Q 2068.
The dialing plan is 7D for home-NPA local calls and 10D across codes.
Largest localities in 231
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Muskegon | 67 | — |
| Traverse City | 53 | — |
| Petoskey | 22 | — |
| Cadillac | 21 | — |
| Big Rapids | 19 | — |
| Ludington | 14 | — |
| Cheboygan | 13 | — |
| Manistee | 12 | — |
| Kalkaska | 10 | — |
| Fremont | 9 | — |
FAQ
Is 231 a toll-free number?
No. 231 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.
Will 231 run out of numbers?
NANPA's current forecast projects exhaust in 1Q 2068 — decades of capacity remain.
Why am I getting spam calls from 231 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 231 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 231 number from?
231 is assigned to Muskegon and surrounding areas of Michigan in the Eastern time zone. The three digits after the area code (the prefix) narrow it down to a rate center.