Phone numbers in Northport, Michigan
Northport has 7 phone prefixes in area code 231.
Biggest holders: Onvoy, 123.NET, AT&T (local phone). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 14%
- Local phone company 14%
- Internet / business phone carrier 43%
- Phone company 29%
Every prefix in Northport
Search the first six digits of a number in this list. If it's here, the number started in Northport with the carrier shown. If it isn't, check the Michigan page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 231-364 | Onvoy | Internet / business phone carrier | 2021 |
| 231-386 | AT&T (local phone) | Local phone company | – |
| 231-432 | AT&T Mobility | Mobile carrier | 2002 |
| 231-446 | Onvoy | Internet / business phone carrier | 2023 |
| 231-637 | Interactive Services Network | Internet / business phone carrier | 2001 |
| 231-877 | 123.NET | Phone company | – |
| 231-899 | 123.NET | Phone company | 2002 |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number. Source: NANPA central office code records, 2026-10-10.