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: MSSLMTMA0MD

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-203 A Missoula MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-204 A Helena MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-205 A Great Falls MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-299 A Butte MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-504 A Fairfield MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-507 A Whitefish MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-508 A Frenchtown MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-512 A Boulder MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-552 A Missoula MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-564 A Great Falls MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-565 A Butte MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-900 A Ennis MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-902 A Sheridan MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-960 A Dillon MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-966 A Shelby MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      
406-988 A Dillon MT 9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648      

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

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