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: 437

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-437 A Helena MT HLNAMTMAMMD  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 648      
406-437 0 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648   2023-09-28   
406-437 1 Helena MT HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2009-04-09   
406-437 2 Helena MT HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2009-07-06   
406-437 3 Helena MT HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2009-09-14   
406-437 4 Helena MT HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2011-04-04   
406-437 5 Helena MT HLNAMTMADS0  9636 QWEST CORPORATION 648   2008-08-13   
406-437 6 Helena MT HLNAMTMADS0  9636 QWEST CORPORATION 648   2008-08-13   
406-437 7 Helena MT HLNAMTMADS0  9636 QWEST CORPORATION 648   2008-08-13   
406-437 8 Helena MT HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2011-07-08   
406-437 9 Helena MT HLNAMTMAMMD  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 648   2004-09-19   

Last updated: Thu, 20 Nov 2025 13:34:34 UTC

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