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: GRFLMTMADS0

Remotes:

Switch Switch name Switch type
CNRDMTMARS1  CONRAD  5ER 
CSCDMTMARS1  CASCADE  5ER 
DTTNMTMARS1  DUTTON  5ER 
ULM MTMARS1  ULM  5ER 
VGHNMTMARS1  VAUGHN  5ER 
NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-268 A Great Falls MT 9636 QWEST CORPORATION 648      
406-452 A Great Falls MT 9636 QWEST CORPORATION 648      
406-453 A Great Falls MT 9636 QWEST CORPORATION 648      
406-454 A Great Falls MT 9636 QWEST CORPORATION 648      
406-727 A Great Falls MT 9636 QWEST CORPORATION 648      
406-761 A Great Falls MT 9636 QWEST CORPORATION 648      
406-771 A Great Falls MT 9636 QWEST CORPORATION 648      
406-791 A Great Falls MT 9636 QWEST CORPORATION 648      

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

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.