Montana Area Codes
Complete directory of all 1 active area codes serving Montana. The The Treasure State has a population of 1,122,864 (2023 estimate) and uses 1 area code.
About Area Codes in Montana
Montana (MT) is the The Treasure State, located in the West region of the United States. With a 2023 population of 1,122,864 residents, Montana is served by 1 active area code. The state capital is Helena and the largest city is Billings.Montana's official motto is "Oro y Plata."
Area code assignments in Montana follow the North American Numbering Plan (NANP), which has been in effect since 1947. As the state's population and demand for phone numbers grew — driven by the rise of cell phones, fax machines, pagers, and VoIP lines — regulators either split existing area codes geographically or added overlay codes that share the same territory. That's why Montana now has 1 codes: 406.
When you receive a call from a Montana number, the area code tells you only where the number was originally assigned. Because of Local Number Portability (LNP), which took effect in 2003, callers can keep their phone numbers even when moving across state lines. So while a 406 number was once assigned in Montana, the person calling you could be anywhere in the US today.
Time zones in Montana
Montana observes the Mountain time zone. Daylight Saving Time is observed from the second Sunday in March through the first Sunday in November, when clocks shift forward by one hour. When you call a Montana number from outside the state, double-check the local time above each area code detail page to avoid calling at unreasonable hours.
Phone number format in Montana
All Montana phone numbers follow the standard 10-digit NANP format: (NPA) NXX-XXXX. For local calls within Montana, you typically need to dial the full 10-digit number — even for calls within the same area code — because of mandatory 10-digit dialing imposed by the FCC for areas with overlay codes (most of Montana's territory). For long-distance calls within the NANP, dial 1 + area code + 7-digit number.
Frequently asked questions about Montana area codes
How many area codes does Montana have?
Montana currently has 1 active area code: 406.
What is Montana's original area code?
The oldest area code(s) in Montana were assigned in 1947 as part of the original 86 NANP codes. These legacy codes typically covered the entire state at first, then were split as demand grew.
What time zone is Montana in?
Montana is in the Mountain time zone.
Will Montana get more area codes?
As Montana's population and number demand grow, NANPA may assign additional overlay codes. When the current codes run out of available prefixes, regulators announce public hearings and propose new codes. The AreaCodeCentral team tracks these announcements and updates the directory within 24 hours of any new code activation.