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: 221

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-221 A Butte MT   453F ONVOY, LLC - MT 648      
406-221 0 Butte MT GRFLMTMAHMD  073H TELNYX LLC 648   2024-02-16   
406-221 1 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648   2012-12-13   
406-221 2 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648   2012-12-13   
406-221 3 Butte MT HLNAMTMAMMD  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 648   2007-05-16   
406-221 4 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648   2012-12-13   
406-221 5 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648   2012-12-13   
406-221 6 Butte MT MSSLMTAG5MD  6010 NEW CINGULAR WIRELESS PCS, LLC 648   2010-11-05   
406-221 7 Butte MT HLNAMTHH5MD  792K CHARTER IP ENABLED SERVICES, LLC 648   2008-08-09   
406-221 8 Butte MT GRFLMTMAHMD  073H TELNYX LLC 648   2020-08-07   
406-221 9 Butte MT   520K TDS METROCOM, LLC 648   2025-11-17   

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

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