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: 666

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
531-666 A Fremont NE OMAKNEYW6MD  965H FRACTEL, LLC 644      
531-666 0 Fremont NE   549E ONVOY, LLC - NE 644   2023-08-11   
531-666 1 Fremont NE   939H COMMIO, LLC 644   2022-07-29   
531-666 2 Fremont NE   6701 AERIAL COMMUNICATIONS, INC. 644   2023-06-23   
531-666 3 Fremont NE   6701 AERIAL COMMUNICATIONS, INC. 644   2023-06-23   
531-666 4 Fremont NE   6701 AERIAL COMMUNICATIONS, INC. 644   2023-06-23   
531-666 5 Fremont NE   624H ONVOY SPECTRUM, LLC 644   2021-07-18   
531-666 6 Fremont NE   965H FRACTEL, LLC 644   2019-03-26   
531-666 7 Fremont NE   549E ONVOY, LLC - NE 644   2023-08-11   
531-666 8 Fremont NE   5807 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - NE 644   2023-07-21   
531-666 9 Fremont NE   549E ONVOY, LLC - NE 644   2024-06-29   

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.