Montana · Mountain Time
406 Area Code
Area code 406 is in Montana, serving the entire state of Montana. It is in the Mountain Time zone.
Last updated October 1, 2026 · Source: NANPA
Where is the 406 area code?
406 is a Montana area code covering the entire state of Montana. In the wider directory it sits in the West region.
Cities in the 406 area code
- Billings
- Missoula
- Great Falls
- Bozeman
- Butte
- Helena
- Kalispell
- Belgrade
- Havre
- Anaconda
- Miles City
- Livingston
- Whitefish
- Lewistown
Counties served by 406
Yellowstone County, Missoula County, Gallatin County, Flathead County, Cascade County, Lewis and Clark County, Silver Bow County, Ravalli County, Lake County and Hill County.
Dialing 406
Billings, MT is currently served by the single area code 406, with no overlay. Ten-digit dialing (area code + seven-digit number) always works and is increasingly the norm nationwide; some local calls may still connect with seven digits. If a future overlay is added, 10-digit dialing would become mandatory.
From outside the US, dial +1 406 followed by the seven-digit number.
History of the 406 area code
406 is one of the original area codes assigned in 1947, when AT&T and Bell Laboratories created the North American Numbering Plan and divided the country into the first 86 numbering plan areas. It has served the Billings area ever since.
Is 406 a scam or spam risk?
406 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 406 number on your screen is no guarantee the caller is in Billings, MT or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Explore more
See every code in Montana, compare codes across the West region, or view all Mountain Time codes. You can also browse the 4XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
406 area code FAQ
Where is the 406 area code?
The 406 area code is in Montana, covering the entire state of Montana, in the West region.
What cities are in the 406 area code?
Cities in the 406 area code include Billings, Missoula, Great Falls, Bozeman, Butte, Helena, Kalispell, Belgrade, Havre and Anaconda.
What time zone is 406 in?
406 is in the Mountain Time zone.
When did the 406 area code start?
406 went into service on January 1, 1947 as one of the original 1947 North American area codes.
Do I have to dial 10 digits for 406?
Ten-digit dialing always works, and many areas now require it; some local calls in this area may still connect with seven digits.
Is 406 a toll-free or premium code?
No. 406 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.