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: 312 [Rate centres in NPA 312] [Dial plan for NPA 312]

NXX: 452

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
312-452 A Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 0 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 1 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 2 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 3 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   
312-452 4 Chicago Zone 01-Calumet IL   624H ONVOY SPECTRUM, LLC 358   2025-10-28   

Last updated: Sun, 07 Dec 2025 22:02:11 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.