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]

Block: A

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NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-996 A Helena MT HLNAMTHH5MD  792K CHARTER IP ENABLED SERVICES, LLC 648      
406-997 A Fromberg MT BLNGMTWEMMD  7421 AT&T - LOCAL 650   2024-03-09   
406-998 A Billings MT BLNGMT93DS0  588H AIRUS, INC. - MT 650      
406-999 A Big Sky MT BZMNMTHZDS0  746D MONTANA OPTICOM, LLC - MT 650      

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Last updated: Tue, 29 Sep 2026 03:00:13 UTC

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