Local Calling Guide

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NPA: 301 [Rate centres in NPA 301] [Dial plan for NPA 301]

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NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
301-556 0 Gaithersburg MD WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-556 1 Gaithersburg MD WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-556 2 Gaithersburg MD WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-556 3 Gaithersburg MD BTVLMD12CMA  5562 METROPCS, INC. 236   2004-11-18   
301-556 4 Gaithersburg MD WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-556 5 Gaithersburg MD LARLMDCCDS0  4492 VDL, INC. DBA GLOBAL TELECOM BROKERS - MD 236   2004-05-06   
301-556 6 Gaithersburg MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2004-02-28   
301-556 7 Gaithersburg MD BTVLMD12CMA  5562 METROPCS, INC. 236   2004-02-28   
301-556 8 Gaithersburg MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2005-11-13   
301-556 9 Gaithersburg MD WASHDCTTDS0  7529 TELEPORT COMMUNICATIONS AMERICA, LLC - DC 236      
301-557 A Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236      
301-557 0 Washington Zone 3 MD BTVLMD18GT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 236   2014-09-12   
301-557 1 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 2 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 3 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 4 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 5 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 6 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 7 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 8 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2011-10-29   
301-557 9 Washington Zone 3 MD ARTNVAARXDY  318J COMCAST IP PHONE, LLC 236   2013-09-08   
301-558 A Washington Zone 13 MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2025-08-28   
301-558 0 Washington Zone 13 MD   071F BANDWIDTH.COM CLEC, LLC - MD 236   2026-05-09   
301-558 1 Washington Zone 13 MD   071F BANDWIDTH.COM CLEC, LLC - MD 236   2026-05-09   
301-558 2 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-09-28   
301-558 3 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-09-28   
301-558 4 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-09-28   
301-558 5 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-08-29   
301-558 6 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-09-28   
301-558 7 Washington Zone 13 MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2025-09-25   
301-558 8 Washington Zone 13 MD   876D ONVOY, LLC - MD 236   2025-08-29   
301-558 9 Washington Zone 13 MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 236   2025-08-28   
301-559 A Washington Zone 4 MD HYVLMDCMDS0  9212 VERIZON MARYLAND, INC. 236      
301-560 A Washington Zone 4 MD   829J PAETEC ITEL, LLC 236   2025-04-02   
301-561 A Washington Zone 3 MD VINNVACB2MD  8697 BALTIMORE-WASHINGTON TELEPHONE (BWT) 236      
301-562 A Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 A Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 0 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 1 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 2 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 3 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 4 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 5 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 6 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 7 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 8 Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-563 9 Washington Zone 3 MD MCLNVA23DS4  6119 LEVEL 3 COMMUNICATIONS, LLC - MD 236   2007-12-04   
301-564 A Washington Zone 2 MD BTHSMDWWDS0  9212 VERIZON MARYLAND, INC. 236      
301-565 A Washington Zone 3 MD SLSPMDSSDS0  9212 VERIZON MARYLAND, INC. 236      
301-566 A Washington Zone 13 MD MRKKMDMKDS0  9212 VERIZON MARYLAND, INC. 236      

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Last updated: Fri, 10 Jul 2026 02:55:48 UTC

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