Local Calling Guide

Area code/prefix search

Search area code/prefix (NPA/NXX)
  • Effective date searches are available only for US area codes. Our sources for non-US NPA-NXX data do not provide this information.
  • If you want to search an entire area code regardless of activity, leave both the next and past days fields set to zero.

Switch: BLNGMTAS9MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
307-227 A Mammoth WY 450F ONVOY, LLC - WY 650      
307-424 A Lake WY 450F ONVOY, LLC - WY 650      
307-427 A Mammoth WY 450F ONVOY, LLC - WY 650      
307-430 A Old Faithful WY 450F ONVOY, LLC - WY 650   2024-02-12   
406-272 A Billings MT 453F ONVOY, LLC - MT 650      
406-290 A Columbus MT 453F ONVOY, LLC - MT 650      
406-306 A Manhattan MT 453F ONVOY, LLC - MT 650      
406-341 A Manhattan MT 453F ONVOY, LLC - MT 650      
406-412 A Billings MT 453F ONVOY, LLC - MT 650      
406-416 A Forsyth MT 453F ONVOY, LLC - MT 650      
406-418 A Cooke City MT 453F ONVOY, LLC - MT 650      
406-518 A Gallatin Gateway MT 453F ONVOY, LLC - MT 650      
406-577 A Bozeman MT 453F ONVOY, LLC - MT 650      
406-616 A Three Forks MT 453F ONVOY, LLC - MT 650      
406-629 A Hardin MT 453F ONVOY, LLC - MT 650      
406-794 A Billings MT 453F ONVOY, LLC - MT 650      
406-800 A Bridger MT 453F ONVOY, LLC - MT 650      
406-804 A Gardiner MT 453F ONVOY, LLC - MT 650      
406-812 A Laurel MT 453F ONVOY, LLC - MT 650      
406-905 A Joliet MT 453F ONVOY, LLC - MT 650      
701-695 A East Fairview ND 452F ONVOY, LLC - ND 650      
701-829 A East Sidney ND 452F ONVOY, LLC - ND 650      

Last updated: Thu, 01 Jan 2026 03:59:49 UTC

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