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: 505

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-505 A Conrad MT MSSLMTAG5MD  6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-505 0 Conrad MT   6010 NEW CINGULAR WIRELESS PCS, LLC 648   2010-11-28   
406-505 1 Conrad MT   073H TELNYX LLC 648   2020-08-07   
406-505 2 Conrad MT   453F ONVOY, LLC - MT 648   2021-02-11   
406-505 3 Conrad MT   453F ONVOY, LLC - MT 648   2021-02-11   
406-505 4 Conrad MT   453F ONVOY, LLC - MT 648   2019-09-15   
406-505 5 Conrad MT   453F ONVOY, LLC - MT 648   2019-10-28   
406-505 6 Conrad MT   508J CENTURYLINK COMMUNICATIONS, LLC 648   2014-05-24   
406-505 7 Conrad MT   453F ONVOY, LLC - MT 648   2011-10-21   
406-505 8 Conrad MT   624H ONVOY SPECTRUM, LLC 648   2021-07-18   
406-505 9 Conrad MT   624H ONVOY SPECTRUM, LLC 648   2021-11-14   

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

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.