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: 531 [Rate centres in NPA 531] [Dial plan for NPA 531]

NXX: 221

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
531-221 A South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640      
531-221 1 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2020-06-15   
531-221 2 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2019-07-01   
531-221 3 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2019-10-31   
531-221 4 South Yankton NE SXFLSDCOX0X  624H ONVOY SPECTRUM, LLC 640   2021-07-18   
531-221 5 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2019-09-16   
531-221 6 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2021-03-19   
531-221 7 South Yankton NE SXFLSDCOTMD  549E ONVOY, LLC - NE 640   2021-03-19   
531-221 8 South Yankton NE SXFLSDCOX0X  624H ONVOY SPECTRUM, LLC 640   2021-10-31   
531-221 9 South Yankton NE SXFLSDCONMD  6534 NEW CINGULAR WIRELESS PCS, LLC - IL 640   2022-06-19   

Last updated: Sun, 26 Jan 2025 15:59:20 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.