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: MSSLMTXC3MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-410 9 Helena MT 939H COMMIO, LLC 648   2023-08-17   
406-479 8 Butte MT 939H COMMIO, LLC 648   2023-08-17   
406-519 6 Missoula MT 939H COMMIO, LLC 648   2023-09-22   
406-923 A Great Falls MT 939H COMMIO, LLC 648      
406-923 3 Great Falls MT 939H COMMIO, LLC 648   2023-03-26   

Last updated: Sun, 26 Jan 2025 15:59:20 UTC

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