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: 439

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-439 A Helena MT MSSLMTAG5MD  6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 0 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 1 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 2 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 3 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 4 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 5 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 6 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 7 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 8 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-439 9 Helena MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648      

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

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