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: 420

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-420 A Bigfork MT KLSLMTAZ1MD  792K CHARTER IP ENABLED SERVICES, LLC 648      
406-420 0 Bigfork MT   9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648   2020-06-09   
406-420 1 Bigfork MT   453F ONVOY, LLC - MT 648   2020-01-13   
406-420 2 Bigfork MT   792K CHARTER IP ENABLED SERVICES, LLC 648   2006-04-21   
406-420 3 Bigfork MT   453F ONVOY, LLC - MT 648   2012-12-10   
406-420 4 Bigfork MT   453F ONVOY, LLC - MT 648   2012-12-10   
406-420 5 Bigfork MT   453F ONVOY, LLC - MT 648   2012-12-10   
406-420 6 Bigfork MT   453F ONVOY, LLC - MT 648   2011-02-28   
406-420 7 Bigfork MT   453F ONVOY, LLC - MT 648   2007-04-14   
406-420 8 Bigfork MT   453F ONVOY, LLC - MT 648   2010-04-03   
406-420 9 Bigfork MT   453F ONVOY, LLC - MT 648   2019-09-15   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

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