Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
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NPA: 406 [Rate centres in NPA 406] [Dial plan for NPA 406]

NXX: 997

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-997 A Fromberg MT BLNGMTWEMMD  7421 AT&T - LOCAL 650   2024-03-09   
406-997 0 Fromberg MT BLNGMTWEDMD  624H ONVOY SPECTRUM, LLC 650   2024-03-22   
406-997 1 Fromberg MT   994E BANDWIDTH.COM CLEC, LLC - MT 650   2026-09-03   
406-997 2 Fromberg MT   6529 T-MOBILE USA, INC. 650   2026-10-17   
406-997 9 Fromberg MT BLNGMTWEMMD  7421 AT&T - LOCAL 650   2024-03-09   

Last updated: Sat, 10 Oct 2026 15:24:20 UTC

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