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 10, MD

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

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
301-296 A WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 0 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 1 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 2 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 3 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 4 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 5 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 6 ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2013-08-01   
301-296 7 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 8 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-296 9 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-299 A BTHSMDBDDS0  9212 VERIZON MARYLAND, INC. 236      
301-309 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 0 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 1 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 2 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 3 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 4 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 5 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 6 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 7 WASKDCFNAMD  6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 236   2021-08-20   
301-309 8 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-309 9 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-315 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-339 A   829J PAETEC ITEL, LLC 236   2025-04-02   
301-339 0   829J PAETEC ITEL, LLC 236      
301-339 1   829J PAETEC ITEL, LLC 236      
301-339 2   829J PAETEC ITEL, LLC 236      
301-339 3 BTVLMD12CMA  6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2006-12-15   
301-339 4 BTVLMD12CMA  6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2006-10-30   
301-339 5   829J PAETEC ITEL, LLC 236      
301-339 6 LARLMDCC5MD  7591 LEVEL 3 TELECOM OF MARYLAND, LLC - MD 236   2012-03-02   
301-339 7   829J PAETEC ITEL, LLC 236   2006-12-21   
301-339 8 ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2012-12-01   
301-339 9   829J PAETEC ITEL, LLC 236      
301-340 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-353 A GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-354 A WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 0 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 1 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 2 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 3 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 4 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 5 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 6 WASIDCRG7MD  508J CENTURYLINK COMMUNICATIONS, LLC 236   2013-10-01   
301-354 7 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 8 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-354 9 WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-398 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-398 0 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 1 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 2 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 3 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 4 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 5 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 6 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2003-11-09   
301-398 7 VINNVACBDS0  876D ONVOY, LLC - MD 236   2003-11-09   
301-398 8 VINNVACBDS0  876D ONVOY, LLC - MD 236   2003-11-09   
301-398 9 VINNVACBDS0  876D ONVOY, LLC - MD 236   2003-11-09   
301-417 A GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 0 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 1 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 2 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 3   829J PAETEC ITEL, LLC 236   2015-09-17   
301-417 4 ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2015-04-14   
301-417 5 VINNVACBDS0  876D ONVOY, LLC - MD 236   2015-06-27   
301-417 6 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 7 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-417 8 ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2015-10-15   
301-417 9 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236      
301-424 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-428 A GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 A GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 0 GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 1 GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 2 GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 3 GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 4 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236   2007-02-06   
301-444 5   515J IP HORIZON LLC 236   2007-09-13   
301-444 6 SLSPMD91DS0  568G PEERLESS NETWORK OF MARYLAND, LLC 236   2020-03-18   
301-444 7 GTBGMDGBPS0  9212 VERIZON MARYLAND, INC. 236   2004-06-10   
301-444 8 GMTWMDGNDS0  9212 VERIZON MARYLAND, INC. 236      
301-444 9 WASHDC127MD  073H TELNYX LLC 236   2020-01-28   
301-461 A WASKDCFNAMD  6395 CELLCO PARTNERSHIP DBA VERIZON WIRELESS - MD 236      
301-517 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 0 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 1 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 2 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 3 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 4 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 5 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 6 VINNVACBDS0  876D ONVOY, LLC - MD 236   2018-01-13   
301-517 7 WASHDC127MD  073H TELNYX LLC 236   2017-03-14   
301-517 8 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-517 9 VINNVACBDS0  876D ONVOY, LLC - MD 236   2018-01-13   
301-529 A BTVLMD18GT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 236      
301-544 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-545 A RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-545 0 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      
301-545 1 RKVLMDRVDS1  9212 VERIZON MARYLAND, INC. 236      

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

Last updated: Mon, 15 Sep 2025 02:24:40 UTC

Sponsored by: ISP Telecom

Like this site? We accept donations via PayPal.