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.

NPA: 443 [Rate centres in NPA 443] [Dial plan for NPA 443]

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 >>

NPA-NXX BLOCK Rate Centre Region Switch OCN LATA LIR Eff date Disc date
443-634 1 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 2 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 3 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 4 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 5 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 6 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 7 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 8 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-634 9 Waterloo (Washington DC LATA) MD   9212 VERIZON MARYLAND, INC. 236   2012-01-08   
443-635 A Baltimore MD CLMAMDORGT0  4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238      
443-635 0 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 1 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 2 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 3 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 4 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 5 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 6 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 7 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 8 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-635 9 Baltimore MD   4036 NEW CINGULAR WIRELESS PCS, LLC - DC 238   2009-12-13   
443-636 A Catonsville MD BLTMMDCH40Z  6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238      
443-636 0 Catonsville MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2008-03-31   
443-636 1 Catonsville MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2007-05-30   
443-636 2 Catonsville MD   829J PAETEC ITEL, LLC 238   2006-02-12   
443-636 3 Catonsville MD   829J PAETEC ITEL, LLC 238   2006-02-25   
443-636 4 Catonsville MD   568G PEERLESS NETWORK OF MARYLAND, LLC 238   2013-05-04   
443-636 5 Catonsville MD   318J COMCAST IP PHONE, LLC 238   2007-08-13   
443-636 6 Catonsville MD   281E YMAX COMMUNICATIONS CORP. - MD 238   2007-08-20   
443-636 7 Catonsville MD   6855 OMNIPOINT COMMUNICATIONS CAP OPERATIONS, LLC 238   2008-07-17   
443-636 8 Catonsville MD   281E YMAX COMMUNICATIONS CORP. - MD 238   2008-07-27   
443-636 9 Catonsville MD   281E YMAX COMMUNICATIONS CORP. - MD 238   2008-07-27   
443-637 A Armiger-Gibson Island MD BLTMMDCHXNX  7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238      
443-637 0 Armiger-Gibson Island MD   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238      
443-637 1 Armiger-Gibson Island MD   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 238   2005-01-10   
443-637 2 Armiger-Gibson Island MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2010-11-29   
443-637 3 Armiger-Gibson Island MD   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238      
443-637 4 Armiger-Gibson Island MD   6119 LEVEL 3 COMMUNICATIONS, LLC - MD 238   2003-02-20   
443-637 5 Armiger-Gibson Island MD   7229 MCIMETRO ACCESS TRANSMISSION SERVICES LLC 238      
443-637 6 Armiger-Gibson Island MD   876D ONVOY, LLC - MD 238   2012-10-07   
443-637 7 Armiger-Gibson Island MD   568G PEERLESS NETWORK OF MARYLAND, LLC 238   2012-10-11   
443-637 8 Armiger-Gibson Island MD   568G PEERLESS NETWORK OF MARYLAND, LLC 238   2012-10-11   
443-637 9 Armiger-Gibson Island MD   568G PEERLESS NETWORK OF MARYLAND, LLC 238   2012-10-11   
443-638 A Ellicott City MD BLTMMDDN4MD  2554 GLOBAL NAPS SOUTH, INC. - MD 238      
443-639 A Hampstead MD   829J PAETEC ITEL, LLC 238   2025-04-01   
443-639 0 Hampstead MD   073H TELNYX LLC 238   2017-04-26   
443-639 1 Hampstead MD   876D ONVOY, LLC - MD 238   2024-05-23   
443-639 2 Hampstead MD   318J COMCAST IP PHONE, LLC 238   2017-07-07   
443-639 3 Hampstead MD   829J PAETEC ITEL, LLC 238      
443-639 4 Hampstead MD   071F BANDWIDTH.COM CLEC, LLC - MD 238   2015-06-04   
443-639 5 Hampstead MD   318J COMCAST IP PHONE, LLC 238   2015-04-02   

<< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 >>

Last updated: Thu, 29 Jan 2026 14:35:03 UTC

Sponsored by: VoIP Much Phone Company

Like this site? We accept donations via PayPal.