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: 604

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
815-604 A Belvidere IL RCFRILRTZMD  224C ONVOY, LLC 360      
815-604 0 Belvidere IL   073H TELNYX LLC 360   2020-06-12   
815-604 1 Belvidere IL   495J STRATUS NETWORKS 360   2020-12-13   
815-604 4 Belvidere IL   224C ONVOY, LLC 360   2023-06-05   
815-604 6 Belvidere IL   224C ONVOY, LLC 360   2019-08-31   
815-604 7 Belvidere IL   224C ONVOY, LLC 360   2019-08-31   
815-604 8 Belvidere IL   224C ONVOY, LLC 360   2019-08-30   
815-604 9 Belvidere IL   224C ONVOY, LLC 360   2024-07-15   

Last updated: Tue, 13 Jan 2026 21:50:02 UTC

Sponsored by: FiberConX Communications Ltd.

Like this site? We accept donations via PayPal.