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: 742

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-742 A Fairview MT FRVWMTMARS2  7830 MID-RIVERS TELEPHONE COOPERATIVE, INC. 650      
406-742 0 Fairview MT   073H TELNYX LLC 650   2018-07-25   
406-742 1 Fairview MT   453F ONVOY, LLC - MT 650   2021-03-28   
406-742 2 Fairview MT   453F ONVOY, LLC - MT 650   2019-09-15   
406-742 3 Fairview MT   145J TERRA NOVA TELECOM INC. 650   2021-01-21   
406-742 4 Fairview MT   453F ONVOY, LLC - MT 650   2019-09-15   
406-742 5 Fairview MT   7830 MID-RIVERS TELEPHONE COOPERATIVE, INC. 650      
406-742 6 Fairview MT   453F ONVOY, LLC - MT 650   2021-07-05   
406-742 7 Fairview MT   508J CENTURYLINK COMMUNICATIONS, LLC 650   2016-08-11   
406-742 8 Fairview MT   624H ONVOY SPECTRUM, LLC 650   2025-01-16   
406-742 9 Fairview MT   7830 MID-RIVERS TELEPHONE COOPERATIVE, INC. 650      

Last updated: Thu, 01 Jan 2026 03:59:49 UTC

Sponsored by: BeeVox - Whitelabel Reseller Platform

Like this site? We accept donations via PayPal.