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: 503

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-503 A Billings MT BLNGMTWELMD  318J COMCAST IP PHONE, LLC 650      
406-503 0 Billings MT BLNGMTAS9MD  453F ONVOY, LLC - MT 650      
406-503 1 Billings MT BLNGMTWELMD  318J COMCAST IP PHONE, LLC 650      
406-503 2 Billings MT   6529 T-MOBILE USA, INC. 650      
406-503 3 Billings MT   453F ONVOY, LLC - MT 650      
406-503 4 Billings MT BLNGMTMAXMD  5562 METROPCS, INC. 650      
406-503 5 Billings MT   453F ONVOY, LLC - MT 650      
406-503 6 Billings MT   453F ONVOY, LLC - MT 650      
406-503 7 Billings MT   453F ONVOY, LLC - MT 650      
406-503 8 Billings MT BLNGMTAS9MD  453F ONVOY, LLC - MT 650      
406-503 9 Billings MT BLNGMTAS9MD  453F ONVOY, LLC - MT 650      

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.