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: 520

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-520 A Absarokee MT BLNGMT93BMD  321J HD CARRIER LLC 650      
406-520 0 Absarokee MT   145J TERRA NOVA TELECOM INC. 650   2025-08-29   
406-520 1 Absarokee MT   6529 T-MOBILE USA, INC. 650   2026-10-17   
406-520 5 Absarokee MT BLNGMT93BMD  321J HD CARRIER LLC 650   2020-09-27   
406-520 6 Absarokee MT BLNGMT93BMD  321J HD CARRIER LLC 650   2020-11-01   

Last updated: Sat, 10 Oct 2026 15:24:20 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.