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: 858 [Rate centres in NPA 858] [Dial plan for NPA 858]

NXX: 344

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
858-344 A La Jolla CA SNDGCA51CM3  6010 NEW CINGULAR WIRELESS PCS, LLC 732      

Last updated: Fri, 25 Jul 2025 03:21:23 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.