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.

Washington Zone 13, MD

<< 1 2 3 4 5 6

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
301-953 5 WASHDCSWMMD  624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-953 6   876D ONVOY, LLC - MD 236   2025-04-06   
301-953 7 LARLMDLRDS0  9212 VERIZON MARYLAND, INC. 236      
301-953 8 LARLMDLRDS0  9212 VERIZON MARYLAND, INC. 236      
301-953 9 LARLMDLRDS0  9212 VERIZON MARYLAND, INC. 236      
301-982 A CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-993 A CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      

<< 1 2 3 4 5 6

Last updated: Thu, 05 Feb 2026 23:41:55 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.