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: HYSHMTXCRS1

NPA-NXX BLOCK Rate Centre Region OCN LATA LIR Eff date Disc date
406-342 A Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 0 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 1 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 4 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 5 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 6 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 7 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 8 Hysham MT 2251 RANGE TEL COOP INC 650      
406-342 9 Hysham MT 2251 RANGE TEL COOP INC 650      

Last updated: Thu, 16 Jul 2026 02:21:55 UTC

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