Area code 406: where it is and who calls from it
Area code 406 is in Montana.
Montana (all)
| Where | Montana |
|---|---|
| Time zone | Mountain Time ยท local time |
| In service since | 1947 |
| Overlay | No |
| Prefixes assigned | 754 of 792 possible (95%) |
Where 406 numbers started
Every prefix is assigned to a rate center, the local calling area it was set up in. These are the biggest in 406, with how many prefixes each has.
Plus 200 smaller rate centers.
Who holds 406 numbers
- Mobile carrier 28%
- Local phone company 30%
- Internet / business phone carrier 19%
- Phone company 23%
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| CenturyLink / Lumen | Local phone company | 158 | 21% |
| Verizon Wireless | Mobile carrier | 119 | 16% |
| AT&T Mobility | Mobile carrier | 74 | 10% |
| Onvoy | Internet / business phone carrier | 45 | 6% |
| Triangle Tel. Coop. Assn | Phone company | 39 | 5% |
| Nemont Tel Coop | Local phone company | 33 | 4% |
| Level 3 (Lumen) | Internet / business phone carrier | 27 | 4% |
| Mid-rivers Tel. Coop | Phone company | 27 | 4% |
| 3 Rivers Tel. Coop | Phone company | 26 | 3% |
| Charter / Spectrum | Internet / business phone carrier | 26 | 3% |
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.
States served: Montana.
Got a call from 406?
An area code tells you where a number was first assigned, not where the caller is. People keep their numbers when they move, and scammers can fake any number. If you weren't expecting the call, let it go to voicemail.
If the call shows a 406 number that matches the first six digits of your own, that's often neighbor spoofing. Use the box above to check the full number.
Area code facts from the NANPA area code database (updated 10/06/2026); prefixes and carriers from NANPA's central office code records (updated 2026-10-10). Place description adapted from Wikipedia, CC BY-SA 4.0.