─────── § 04. NPA RECORD · 406 · FOLIO 0208 OF 0801 ──────────────
406
United States NPA Record
Area code 406 is the sole telephone area code for the entire state of Montana, established in 1947 as part of the original North American Numbering Plan.
Area code 406 is the sole telephone area code for the entire state of Montana, established in 1947 as part of the original North American Numbering Plan. It remains the only area code serving Montana, covering all communities statewide.
IN SERVICEFirst record · 1947
§ 04.05Event Summary
introduced · 1mandatory dialing · 1other · 1permissive dialing · 1relief planned · 1service expansion · 1
§ 04.06
Documentary Record · 6 events
CHRONOLOGICAL ORDER
1947-01-01
introduced
Area code 406 introduced for Montana
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2013-05-23
service expansion
FCC grants Montana PSC authority for mandatory number pooling in 406
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2020-07-16
other
FCC designates 988 as National Suicide Prevention Lifeline code
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2021-04-24
permissive dialing
Permissive ten-digit dialing begins in area code 406
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2021-10-24
mandatory dialing
Mandatory ten-digit dialing implemented in area code 406
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2031-01-01
relief planned
Projected exhaustion of area code 406
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