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.

NPA: 406 [Rate centres in NPA 406] [Dial plan for NPA 406]

NXX: 389

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-389 A Helena MT HLNAMTMAUMD  508J CENTURYLINK COMMUNICATIONS, LLC 648      
406-389 0 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 1 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 2 Helena MT HLNAMTMAUMD  508J CENTURYLINK COMMUNICATIONS, LLC 648      
406-389 3 Helena MT HLNAMTMAMMD  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 648      
406-389 4 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 5 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 6 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 7 Helena MT HLNAMTMAUMD  508J CENTURYLINK COMMUNICATIONS, LLC 648      
406-389 8 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-389 9 Helena MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      

Last updated: Wed, 20 Nov 2024 21:20:06 UTC

Sponsored by: LES.NET

Like this site? We accept donations via PayPal.