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: 661

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
510-661 A Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 0 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 1 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 2 Fremont-Newark: Oliver DA CA SNTDCAUJCM9  6010 NEW CINGULAR WIRELESS PCS, LLC 722   2021-12-11   
510-661 3 Fremont-Newark: Oliver DA CA SNFCCAMKDS3  649C ONVOY, LLC - CA 722   2014-09-25   
510-661 4 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 5 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 6 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 7 Fremont-Newark: Oliver DA CA SNFCCAMKX1X  9262 UTILITY TELECOM GROUP, LLC - CA 722      
510-661 8 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      
510-661 9 Fremont-Newark: Oliver DA CA FRMTCA12DS0  9740 PACIFIC BELL 722      

Last updated: Mon, 15 Sep 2025 02:24:40 UTC

Sponsored by: VoIP.ms

Like this site? We accept donations via PayPal.