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.

Chester, MT

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
406-759 A HAVRMTXCDS0  2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-759 2 MSSLMTMA0MD  9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648   2019-11-25   
406-759 5 HAVRMTXCDS0  2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-759 6 HAVRMTXCDS0  2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-759 8 HAVRMTXCDS0  2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-759 9 HLNAMTMAX1X  6564 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MT 648   2020-02-24   

Last updated: Sat, 15 Nov 2025 03:38:44 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.