Area code
Area code 231 — Muskegon, MI
Michigan · in service since June 5, 1999
Area code 231 covers parts of Michigan; the place with the most of its prefixes is Muskegon. It was created from area code 616 on June 5, 1999 and no other code overlays it.
Local time in Muskegon
Spam reports from Sep 23 – Oct 22, 2026
High #45 of 461 codes
861 FTC complaints
Consumer reports, not verified by the FTC.
See the reports- Time zoneEastern Time
- Local calls7 digits
- Prefixes596 assigned
- Runs out~1Q 2068
- Unwanted call?Block & report
Spam call reports about 231 numbers
Complaints by week
Sep 11 – Oct 22, 2026Show as table
| Week starting | Complaints |
|---|---|
| Sep 7 (3 days) | 45 |
| Sep 14 | 192 |
| Sep 21 | 190 |
| Sep 28 | 143 |
| Oct 5 | 198 |
| Oct 12 | 203 |
| Oct 19 (4 days) | 186 |
Compared with all codes
- Robocalls
- 71%all codes 75%
- Callers with the same code
- 43%all codes 35%
- Rank by complaints
- #45of 461 · top tenth (most complaints)
- FCC complaints, Oct 2025 – Sep 2026
- 10811 about text messages
What the calls were about
Sep 11 – Oct 22, 2026
| Subject | Complaints | |
|---|---|---|
| Reducing your debt (credit cards, mortgage, student loans) | 338 29% | |
| Dropped call or no message | 87 8% | |
| Medical & prescriptions | 69 6% | |
| Calls pretending to be government, businesses, or family and friends | 64 6% | |
| Warranties & protection plans | 8 1% | |
| Home improvement & cleaning | 7 1% |
Where the people who complained live
Sep 11 – Oct 22, 2026
| State | Complaints | |
|---|---|---|
| Michigan | 606 52% | |
| California | 69 6% | |
| Florida | 57 5% | |
| Illinois | 45 4% | |
| Georgia | 28 2% |
October 2026 (partial) report · most reported
Consumer reports, not verified by the FTC · source
Source: FTC Do Not Call complaints created Sep 11 – Oct 22, 2026. They are reported by consumers and are not verified by the FTC; caller ID can be spoofed (how we count).
Source: FCC Consumer Complaints data, unwanted calls filed Oct 1, 2025 – Sep 30, 2026, by caller ID; not verified by the FCC.
Area code 231 location and prefixes
| Exchange (NANPA) | Place | County | Prefixes |
|---|---|---|---|
| MUSKEGON | Muskegon | Muskegon County | 68 |
| TRAVERSECY | Traverse City | spans 2 counties | 53 |
| PETOSKEY | Petoskey | Emmet County | 22 |
| CADILLAC | Cadillac | Wexford County | 21 |
| BIG RAPIDS | Big Rapids | Mecosta County | 19 |
| LUDINGTON | Ludington | Mason County | 14 |
| CHEBOYGAN | Cheboygan | Cheboygan County | 13 |
| MANISTEE | Manistee | Manistee County | 12 |
| KALKASKA | Kalkaska | Kalkaska County | 10 |
| FREMONT | Fremont | Newaygo County | 9 |
Plus 89 smaller exchange areas.
Source: NANPA CO codes of Oct 23, 2026; places: U.S. Census Bureau, matched by DialWhere (how).
Is 231 running out of numbers?
Previous forecast (October 2025): 2056, moved later by 12 years.
Forecast exhaust year by edition
Source: NANPA NRUF forecast, April 2026 edition.
Who holds 231 prefixes
The five largest of 44 original holders
As listed by NANPA, not today’s carrier.
| Holder (as listed) | Prefixes | |
|---|---|---|
| Michigan Bell Tel Co. | 72 12% | |
| New Cingular Wireless PCS, LLC | 72 12% | |
| Frontier North, Inc. | 52 9% | |
| Onvoy, Llcv | 49 8% | |
| Interactive Services Network, Inc. | 43 7% |
Source: NANPA CO codes of Oct 23, 2026.
Questions about area code 231
What area code is 231?
A Michigan area code, in service since June 5, 1999.
Where is 231 area code, and what time zone is it in?
Muskegon, MI; Eastern Time.
Why am I getting spam calls from 231?
861 FTC complaints from Sep 23 – Oct 22, 2026, most often about debt reduction (not verified by the FTC; caller ID can be spoofed).
Will 231 get a new area code?
NANPA forecasts exhaust in 1Q 2068; no relief planning listed.