Phone numbers in Fitchburg, Michigan
Fitchburg has 3 phone prefixes in area code 517.
Biggest holders: Frontier, Interactive Services Network, Acd Telecom. This is the local calling area (rate center) where those prefixes were first assigned.
- Local phone company 33%
- Internet / business phone carrier 33%
- Phone company 33%
Every prefix in Fitchburg
Search the first six digits of a number in this list. If it's here, the number started in Fitchburg with the carrier shown. If it isn't, check the Michigan page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 517-565 | Frontier | Local phone company | – |
| 517-634 | Interactive Services Network | Internet / business phone carrier | 2002 |
| 517-923 | Acd Telecom | Phone company | 2001 |
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.