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 11, MD

<< 1 2 3 4 5 6 7 >>

NPA-NXX BLOCK Switch OCN LATA LIR Eff date Disc date
301-231 1 VINNVACBDS0  876D ONVOY, LLC - MD 236   2014-09-01   
301-231 2 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 3 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 4 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 5 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 6 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 7 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 8 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-231 9 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 A RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 0 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 1 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 2 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 3 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 4 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 5 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 6 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 7 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 8 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236      
301-255 9   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-10-24   
301-287 A WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-287 0 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-287 1   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-10-24   
301-287 2 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-287 3 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-287 4 VINNVACBDS0  876D ONVOY, LLC - MD 236   2017-12-08   
301-287 5 VINNVACBDS0  876D ONVOY, LLC - MD 236   2017-12-08   
301-287 6 VINNVACBDS0  876D ONVOY, LLC - MD 236   2017-12-08   
301-287 7   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-03-29   
301-287 8   829J PAETEC ITEL, LLC 236   2004-03-27   
301-287 9 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-321 A VINNVACBDS0  876D ONVOY, LLC - MD 236      
301-321 0   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-321 1 SLSPMD913MD  939H COMMIO, LLC 236   2021-08-29   
301-321 2   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-321 3   829J PAETEC ITEL, LLC 236   2014-06-09   
301-321 4 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2016-09-01   
301-321 5 RKVLMDMRDS0  9212 VERIZON MARYLAND, INC. 236   2005-12-12   
301-321 6   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-06-16   
301-321 7 VINNVACBDS0  876D ONVOY, LLC - MD 236   2016-01-07   
301-321 8 VINNVACBDS0  876D ONVOY, LLC - MD 236   2016-01-07   
301-321 9   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-10-24   
301-348 A WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-348 0   2593 CORE COMMUNICATIONS, INC.- MD 236   2018-10-24   
301-348 1 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-348 2   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-29   
301-348 3 WASKDCFNPS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236      
301-348 4   2593 CORE COMMUNICATIONS, INC.- MD 236   2019-04-29   
301-348 5 WASHDCINDS0  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 236   2017-08-03   
301-348 6   2593 CORE COMMUNICATIONS, INC.- MD 236   2012-08-26   

<< 1 2 3 4 5 6 7 >>

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

Sponsored by: LES.NET

Like this site? We accept donations via PayPal.