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: 815 [Rate centres in NPA 815] [Dial plan for NPA 815]

NXX: 357

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
815-357 A Seneca IL SENCILSNRS0  9329 ILLINOIS BELL TEL CO 358      
815-357 0 Seneca IL   495J STRATUS NETWORKS 358   2020-09-26   
815-357 1 Seneca IL   9329 ILLINOIS BELL TEL CO 358      
815-357 2 Seneca IL   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 358   2018-07-12   
815-357 4 Seneca IL   224C ONVOY, LLC 358   2012-04-15   
815-357 5 Seneca IL   9329 ILLINOIS BELL TEL CO 358      
815-357 6 Seneca IL   9329 ILLINOIS BELL TEL CO 358      
815-357 7 Seneca IL   984E BANDWIDTH.COM CLEC, LLC - IL 358   2012-01-12   
815-357 8 Seneca IL   9329 ILLINOIS BELL TEL CO 358      

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: Callcentric - VoIP Internet phone service

Like this site? We accept donations via PayPal.