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: 309 [Rate centres in NPA 309] [Dial plan for NPA 309]

NXX: 378

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
309-378 A Downs IL DWNSILXDRS0  1015 FRONTIER NORTH, INC. - IL 366      
309-378 0 Downs IL BLTNILXDXPX  846F MEDIACOM TELEPHONY OF ILLINOIS, LLC - IL 366   2010-03-15   
309-378 1 Downs IL DWNSILXDRS0  1015 FRONTIER NORTH, INC. - IL 366      
309-378 2 Downs IL DWNSILXDRS0  1015 FRONTIER NORTH, INC. - IL 366      
309-378 3 Downs IL DWNSILXDRS0  1015 FRONTIER NORTH, INC. - IL 366      
309-378 4 Downs IL DWNSILXDRS0  1015 FRONTIER NORTH, INC. - IL 366      
309-378 6 Downs IL BLTNILXDXHY  624H ONVOY SPECTRUM, LLC 366   2023-06-02   
309-378 8 Downs IL BLTNILATVMD  6115 LEVEL 3 COMMUNICATIONS, LLC - IL 366   2004-07-16   
309-378 9 Downs IL BLTNILTSYMD  495J STRATUS NETWORKS 366   2020-10-14   

Last updated: Sun, 27 Apr 2025 12:48:38 UTC

Sponsored by: Execulink Telecom

Like this site? We accept donations via PayPal.