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: 936

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-936 A Clyde Park MT BLNGMTMALMD  994E BANDWIDTH.COM CLEC, LLC - MT 650      
406-936 0 Clyde Park MT   994E BANDWIDTH.COM CLEC, LLC - MT 650   2015-09-14   
406-936 1 Clyde Park MT   073H TELNYX LLC 650   2018-07-25   
406-936 2 Clyde Park MT   453F ONVOY, LLC - MT 650   2021-03-07   
406-936 3 Clyde Park MT   453F ONVOY, LLC - MT 650   2019-09-15   
406-936 4 Clyde Park MT   453F ONVOY, LLC - MT 650   2019-10-28   
406-936 5 Clyde Park MT   453F ONVOY, LLC - MT 650   2021-03-07   
406-936 6 Clyde Park MT   453F ONVOY, LLC - MT 650   2020-01-05   
406-936 7 Clyde Park MT   6529 T-MOBILE USA, INC. 650   2024-03-15   
406-936 8 Clyde Park MT   453F ONVOY, LLC - MT 650   2021-07-05   
406-936 9 Clyde Park MT   994E BANDWIDTH.COM CLEC, LLC - MT 650   2022-02-12   

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: LES.NET

Like this site? We accept donations via PayPal.