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: 623

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-623 A Hardin MT BLNGMTVR0MD  939H COMMIO, LLC 650      
406-623 0 Hardin MT   6010 NEW CINGULAR WIRELESS PCS, LLC 650   2007-03-18   
406-623 1 Hardin MT   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 650   2023-06-05   
406-623 2 Hardin MT   935G TRI TEL, INC. - MT 650   2013-01-28   
406-623 3 Hardin MT   073H TELNYX LLC 650   2017-03-31   
406-623 4 Hardin MT   9415 LEVEL 3 COMMUNICATIONS, LLC - MT 650   2005-04-09   
406-623 5 Hardin MT   453F ONVOY, LLC - MT 650   2006-10-20   
406-623 6 Hardin MT   939H COMMIO, LLC 650   2023-07-15   
406-623 7 Hardin MT   453F ONVOY, LLC - MT 650   2011-07-17   
406-623 8 Hardin MT   453F ONVOY, LLC - MT 650   2019-10-28   
406-623 9 Hardin MT   994E BANDWIDTH.COM CLEC, LLC - MT 650   2008-11-26   

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

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