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: 831 [Rate centres in NPA 831] [Dial plan for NPA 831]

NXX: 851

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
831-851 A Watsonville CA SNFCCAMKDS3  649C ONVOY, LLC - CA 722   2024-01-21   

Last updated: Thu, 16 Oct 2025 03:04:18 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.