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.

Joplin, MT

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
406-292 A HAVRMTXCDS0  2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-292 1   2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-292 2   9415 LEVEL 3 COMMUNICATIONS, LLC - MT 648   2019-01-18   
406-292 3   2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-292 4   2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-292 7   2257 TRIANGLE TEL. COOP. ASSN., INC. 648      
406-292 9   2257 TRIANGLE TEL. COOP. ASSN., INC. 648      

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.