Phone numbers in Sidney, Montana
Sidney has 9 phone prefixes in area code 406.
Biggest holders: Verizon Wireless, Mid-rivers Telephone Cooperative, Level 3 (Lumen). This is the local calling area (rate center) where those prefixes were first assigned.
- Mobile carrier 44%
- Local phone company 33%
- Internet / business phone carrier 22%
Every prefix in Sidney
Search the first six digits of a number in this list. If it's here, the number started in Sidney with the carrier shown. If it isn't, check the Montana page or look the number up.
| Prefix | Carrier | Type | Assigned |
|---|---|---|---|
| 406-433 | Mid-rivers Telephone Cooperative | Local phone company | – |
| 406-478 | Verizon Wireless | Mobile carrier | – |
| 406-480 | Verizon Wireless | Mobile carrier | – |
| 406-482 | CenturyLink / Lumen | Local phone company | – |
| 406-488 | Mid-rivers Telephone Cooperative | Local phone company | – |
| 406-489 | AT&T Mobility | Mobile carrier | – |
| 406-630 | Level 3 (Lumen) | Internet / business phone carrier | 2005 |
| 406-943 | Level 3 (Lumen) | Internet / business phone carrier | 2003 |
| 406-973 | Verizon Wireless | 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.