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US area code · Montana

406 area code

Where the 406 area code is, its overlay and how to dial a +1 406 number from anywhere.

CoversBillings, MontanaTime zoneMountain (MT)TypeGeographic
Quick answer

The 406 area code is in Billings, Montana, United States (Mountain (MT)). To call from abroad: +1 406 555-0123.

StateMontana
Main areaBillings
Time zoneMountain (MT)
TypeGeographic
10-digit dialingRequired
In service since01-Jan-1947

The 406 area code is a geographic North American Numbering Plan (NANP) code covering Billings, Montana. It has been in service since 01-Jan-1947 and sits in the Mountain (MT) time zone.

How to dial a 406 number

From abroad+1 406 555-0123
Within the US / Canada1 406 555-0123
Locally (same area)406 555-0123

Cities in the 406 area code

A 406 number is usually in one of these places in Montana — 6 counties.

Billings YellowstoneBozeman GallatinButte Silver BowGreat Falls CascadeHelena Lewis And ClarkMissoula Missoula

Frequently asked questions

Where is the 406 area code?

The 406 area code is in Billings, Montana, United States (Mountain (MT)).

Do I have to dial 10 digits for 406?

Yes — dial the area code plus the seven-digit number.

How do I call a 406 number from another country?

Dial your exit code (or +), then 1, then 406, then the number: +1 406 555-0123.

Source: NANPA numbering plan. An area code covers a region, not a precise address — a 406 number does not pinpoint a street or ZIP code.

Number holders in area code 406

Each prefix (the three digits after the area code) is assigned by NANPA to one telephone company. 768 prefixes are in use in 406, shared by 67 companies. The largest holders:

CompanyPrefixesShare
Qwest Corporation13217%
Cellco Partnership Dba Verizon Wireless11915%
New Cingular Wireless PCS, LLC7410%
Onvoy, LLC436%
Triangle Tel. Coop. Assn., Inc.395%
Nemont Tel Coop Inc334%

Source: NANPA central office code assignments. A number keeps its original prefix when it is ported to another carrier.

Complaints about 406 numbers

Reports to the FTC, last 30 days
546
Recorded messages or robocalls
61%
Rank among area codes
#161 of 670
Most reported subjects
Other (301)
Reducing your debt (credit cards, mortgage, student loans) (65)
Dropped call or no message (47)

Period Aug 26 – Sep 24, 2026. These are the numbers shown on the caller ID of the reported calls; many are spoofed and do not belong to the real caller.

Source: US Federal Trade Commission, Do Not Call reported calls data (daily files).

All US area codes United States +1 Map of area code 406 — cities & rate centres

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