Phone numbers in Granite Falls, Minnesota
Granite Falls has 7 phone prefixes in area code 320.
Biggest holders: Level 3 (Lumen), CenturyLink / Lumen, Onvoy. This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 14%
- Local phone company 29%
- Internet / business phone carrier 57%
Every prefix in Granite Falls
Search the first six digits of a number in this list. If it's here, the number started in Granite Falls with the carrier shown. If it isn't, check the Minnesota page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 320-313 | Onvoy | Internet / business phone carrier | 2003 |
| 320-315 | Level 3 (Lumen) | Internet / business phone carrier | 2003 |
| 320-338 | Level 3 (Lumen) | Internet / business phone carrier | 2004 |
| 320-379 | Mcc Telephony Of Minnesota | Internet / business phone carrier | 2010 |
| 320-564 | CenturyLink / Lumen | Local phone company | – |
| 320-722 | CenturyLink / Lumen | Local phone company | 2006 |
| 320-981 | AT&T Mobility | Mobile carrier | – |
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.