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 7 8 9 10 11 >>

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
301-823 5 WASHDC125MD  197D VONAGE AMERICA LLC 236   2020-05-20   
301-823 6   876D ONVOY, LLC - MD 236   2025-03-09   
301-823 7   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-29   
301-823 8 LARLMDCCDS0  4492 VDL, INC. DBA GLOBAL TELECOM BROKERS - MD 236   2004-04-06   
301-823 9 WASHDCSWMMD  624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-837 A WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 0 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 1 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 2 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 3 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 4 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2018-10-28   
301-837 5 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-837 6 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2018-10-28   
301-837 7 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2018-10-28   
301-837 8 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2015-03-14   
301-837 9 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-886 A   071F BANDWIDTH.COM CLEC, LLC - MD 236      
301-886 0   2593 CORE COMMUNICATIONS, INC.- MD 236   2004-03-26   
301-886 1   071F BANDWIDTH.COM CLEC, LLC - MD 236   2025-05-16   
301-886 2   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-15   
301-886 3 CHCHMDBE1MD  8697 BALTIMORE-WASHINGTON TELEPHONE (BWT) 236   2006-05-05   
301-886 4   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-15   
301-886 5   876D ONVOY, LLC - MD 236   2025-08-09   
301-886 6   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-15   
301-886 7   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-15   
301-886 8   829J PAETEC ITEL, LLC 236   2003-04-06   
301-886 9   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2025-08-09   
301-901 A CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-901 0 VINNVACBDS0  876D ONVOY, LLC - MD 236   2023-10-15   
301-901 1 CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-901 2 CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-901 3 VINNVACBDS0  876D ONVOY, LLC - MD 236   2023-10-15   
301-901 4 CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-901 5 VINNVACBDS0  876D ONVOY, LLC - MD 236   2023-10-15   
301-901 6 CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-901 7 VINNVACBDS0  876D ONVOY, LLC - MD 236   2023-10-15   
301-901 8 VINNVACBDS0  876D ONVOY, LLC - MD 236   2023-10-15   
301-901 9 CLPKMDBWDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 A BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 0 VINNVACBDS0  876D ONVOY, LLC - MD 236   2020-12-03   
301-902 1 BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 2 BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 3 BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 4 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-902 5 WASHDCSWMMD  624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-902 6 WASHDCSWMMD  624H ONVOY SPECTRUM, LLC 236   2021-11-08   
301-902 7 ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2019-07-05   
301-902 8 BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-902 9 BTVLMDBVDS0  9212 VERIZON MARYLAND, INC. 236      
301-923 A WASHDCDP8MD  071F BANDWIDTH.COM CLEC, LLC - MD 236      

<< 1 2 3 4 5 6 7 8 9 10 11 >>

Last updated: Sat, 02 May 2026 12:20:53 UTC

Sponsored by: BeeVox - Whitelabel Reseller Platform

Like this site? We accept donations via PayPal.