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: 510 [Rate centres in NPA 510] [Dial plan for NPA 510]

NXX: 250

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
510-250 A Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722      
510-250 0 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722      
510-250 1 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722      
510-250 2 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722   2008-05-16   
510-250 3 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722   2008-05-16   
510-250 4 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722   2006-08-11   
510-250 5 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722      
510-250 6 Oakland: Main-Piedmont DA CA SNJSCAYB0MD  671J U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 722   2007-03-25   
510-250 7 Oakland: Main-Piedmont DA CA SNFCCASY5MD  8826 LEVEL 3 COMMUNICATIONS, LLC - CA 722   2007-12-04   
510-250 8 Oakland: Main-Piedmont DA CA SNJSCAYB0MD  671J U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS 722   2007-03-25   
510-250 9 Oakland: Main-Piedmont DA CA SNFCCA01XGX  516C AT&T CORP. 722   2011-09-30   

Last updated: Sat, 04 Jul 2026 13:07:56 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.