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: 221

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
406-221 A Butte MT HLNAMTMAKMD  7421 AT&T - LOCAL 648      
406-221 0 Butte MT   073H TELNYX LLC 648      
406-221 1 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-221 2 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-221 3 Butte MT HLNAMTMAMMD  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 648      
406-221 4 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-221 5 Butte MT GRFLMTMA7MD  453F ONVOY, LLC - MT 648      
406-221 6 Butte MT MSSLMTAG5MD  6010 NEW CINGULAR WIRELESS PCS, LLC 648      
406-221 7 Butte MT   792K CHARTER IP ENABLED SERVICES, LLC 648      
406-221 8 Butte MT GRFLMTMAHMD  073H TELNYX LLC 648      
406-221 9 Butte MT HLNAMTMAKMD  7421 AT&T - LOCAL 648      

Last updated: Wed, 20 Nov 2024 21:20:06 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.