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: 231

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-231 A Great Falls MT MSSLMTAG5MD  6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 0 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 1 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 2 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 3 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 4 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 5 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 6 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 7 Great Falls MT   6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2026-01-21   
406-231 8 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-231 9 Great Falls MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

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