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: 401

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-401 A Great Falls MT GRFLMTMAX0X  425J CSC WIRELESS, LLC 648      
406-401 0 Great Falls MT   453F ONVOY, LLC - MT 648   2021-02-04   
406-401 1 Great Falls MT   453F ONVOY, LLC - MT 648   2021-02-04   
406-401 2 Great Falls MT   425J CSC WIRELESS, LLC 648   2019-07-20   
406-401 3 Great Falls MT   453F ONVOY, LLC - MT 648   2021-02-04   
406-401 4 Great Falls MT   453F ONVOY, LLC - MT 648   2021-02-04   
406-401 5 Great Falls MT   6529 T-MOBILE USA, INC. 648   2020-12-23   
406-401 6 Great Falls MT   453F ONVOY, LLC - MT 648   2021-07-05   
406-401 7 Great Falls MT   453F ONVOY, LLC - MT 648   2021-07-05   
406-401 8 Great Falls MT   453F ONVOY, LLC - MT 648   2021-07-05   
406-401 9 Great Falls MT   453F ONVOY, LLC - MT 648   2021-07-05   

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

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