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: 857 [Rate centres in NPA 857] [Dial plan for NPA 857]

NXX: 858

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
857-858 A Newton MA BSTPMALLDS3  892D ONVOY, LLC - MA 128      
857-858 0 Newton MA   990E BANDWIDTH.COM CLEC, LLC - MA 128   2023-06-05   
857-858 1 Newton MA   892D ONVOY, LLC - MA 128   2020-07-12   
857-858 2 Newton MA   892D ONVOY, LLC - MA 128   2020-07-12   
857-858 3 Newton MA   892D ONVOY, LLC - MA 128   2020-07-12   
857-858 4 Newton MA   892D ONVOY, LLC - MA 128   2021-04-06   
857-858 5 Newton MA   892D ONVOY, LLC - MA 128   2021-04-06   
857-858 6 Newton MA   892D ONVOY, LLC - MA 128   2021-04-06   
857-858 7 Newton MA   490J DISH WIRELESS, LLC 128   2023-06-05   
857-858 8 Newton MA   624H ONVOY SPECTRUM, LLC 128   2021-04-11   
857-858 9 Newton MA   197D VONAGE AMERICA LLC 128   2021-05-29   

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

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.