406 area code — Billings, MT geographic
- State
- Montana
- Major area
- Billings
- Time zone
- Mountain
- In service since
- 1947-01-01
- Active prefixes
- 753
- Rate centers
- 260
- Carriers
- 62
- Projected exhaust
- 4Q 2033
406 is the area code for Billings, Montana, in service since January 1, 1947, Mountain time. Note that porting and VoIP mean a 406 number can be used from anywhere — the code marks where the number was assigned.
753 central-office prefixes are currently active in this code, spread across 62 code-holding carriers. Thousands-block pooling applies to 525 prefixes, so a single prefix can belong to several carriers. Its prefixes map to 260 distinct rate centers.
If a 406 call asks for money or personal data, treat the displayed number as unverified: hang up and reach the organization through its published number. Numbering data locates numbers, not callers.
Among Montana codes, 406 stands out as the only area code serving Montana.
Dialing: 10D locally, 10D to other codes (1+10 digit permissible at service provider discretion.).
NANPA projects numbering capacity to exhaust in 4Q 2033.
Largest localities in 406
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Billings | 72 | — |
| Missoula | 46 | — |
| Helena | 38 | — |
| Great Falls | 37 | — |
| Bozeman | 32 | — |
| Kalispell | 25 | — |
| Butte | 17 | — |
| Miles City | 10 | — |
| Sidney | 9 | — |
| Livingston | 8 | — |
FAQ
Is 406 a toll-free number?
No. 406 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.
Will 406 run out of numbers?
NANPA's current forecast projects exhaust in 4Q 2033 — decades of capacity remain.
Why am I getting spam calls from 406 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 406 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 406 number from?
406 is assigned to Billings and surrounding areas of Montana in the Mountain time zone. The three digits after the area code (the prefix) narrow it down to a rate center.