Montana numbering plan area and area code (blue)

Area code 406 is the telephone area code in the North American Numbering Plan for the entire U.S. state of Montana. It has been Montana's only area code since the American Telephone and Telegraph Company created a nationwide telephone numbering plan in 1947.

As of 2013, 47 carriers served 1.7 million lines in Montana. All but two wireline providers support local number portability (the exceptions are small rural independents Hot Springs Telephone Company and Northern Telephone Cooperative). Sufficient available codes for new exchanges in the 406 area code exist to meet anticipated demand until 2031; number pooling has been implemented in response to increased demand and inefficient use of 406 numbering resources.

Prior to October 2021, area code 406 had telephone numbers assigned for the central office code 988. In 2020, 988 was designated nationwide as a dialing code for the National Suicide Prevention Lifeline, which created a conflict for exchanges that permit seven-digit dialing. This area code was therefore scheduled to transition to ten-digit dialing by October 24, 2021.

For many Montanans, area code 406 has become an unofficial symbol of the state. Some Montanans celebrate April 6 as "406 Day," an unofficial holiday celebrating the state.

Central office codes of communities

Within the Montana numbering plan area, the following communities are served by the listed central office codes:

See also

External links

Montana area codes: 406
North: 236/672/778, 250, 306, 403, 587/825/368, 639
West: 208/986406East: 605, 701
South: 307
Alberta area codes: 403, 587/825/368, 780
British Columbia area codes: 250, 604, 236/257/672/778
Saskatchewan area codes: 306/474/639
Idaho area codes: 208/986
North Dakota area codes: 701
South Dakota area codes: 605
Wyoming area codes: 307