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: 342

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-342 A Hysham MT HYSHMTXCRS1  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 2 Hysham MT   9415 LEVEL 3 COMMUNICATIONS, LLC - MT 650   2026-06-08   
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: Sat, 02 May 2026 12:20:53 UTC

Sponsored by: BeeVox - Whitelabel Reseller Platform

Like this site? We accept donations via PayPal.