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        <filer>
          <filerCredentials>
            <cik>0001166976</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
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      <issuerInfo>
        <issuerCik>0001158324</issuerCik>
        <issuerName>Cogent Communications Holdings, Inc.</issuerName>
        <secFileNumber>000-51829</secFileNumber>
        <issuerAddress>
          <com:street1>2450 N.  Street  N.W.</com:street1>
          <com:city>Washington</com:city>
          <com:stateOrCountry>DC</com:stateOrCountry>
          <com:zipCode>20037</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>202-295-4200</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>David Schaeffer</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Founder</relationshipToIssuer>
          <relationshipToIssuer>CEO</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue</com:street1>
            <com:street2>6th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>60000</noOfUnitsSold>
        <aggregateMarketValue>3087000</aggregateMarketValue>
        <noOfUnitsOutstanding>49024447</noOfUnitsOutstanding>
        <approxSaleDate>06/14/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>06/01/2010</acquiredDate>
        <natureOfAcquisitionTransaction>Grant Vest</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>60000</amountOfSecuritiesAcquired>
        <paymentDate>11/01/2010</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>David Schaeffer</name>
          <address>
            <com:street1>C/o Cogent Communications Holdings Inc</com:street1>
            <com:street2>2450 N. Street N.W.</com:street2>
            <com:city>Washington</com:city>
            <com:stateOrCountry>DC</com:stateOrCountry>
            <com:zipCode>20037</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <saleDate>03/15/2024</saleDate>
        <amountOfSecuritiesSold>26174</amountOfSecuritiesSold>
        <grossProceeds>1680633</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>David Schaeffer</name>
          <address>
            <com:street1>C/o Cogent Communications Holdings Inc</com:street1>
            <com:street2>2450 N. Street N.W.</com:street2>
            <com:city>Washington</com:city>
            <com:stateOrCountry>DC</com:stateOrCountry>
            <com:zipCode>20037</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <saleDate>05/13/2024</saleDate>
        <amountOfSecuritiesSold>50000</amountOfSecuritiesSold>
        <grossProceeds>2972000</grossProceeds>
      </securitiesSoldInPast3Months>
      <securitiesSoldInPast3Months>
        <sellerDetails>
          <name>David Schaeffer</name>
          <address>
            <com:street1>C/o Cogent Communications Holdings Inc</com:street1>
            <com:street2>2450 N. Street N.W.</com:street2>
            <com:city>Washington</com:city>
            <com:stateOrCountry>DC</com:stateOrCountry>
            <com:zipCode>20037</com:zipCode>
          </address>
        </sellerDetails>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <saleDate>06/12/2024</saleDate>
        <amountOfSecuritiesSold>60000</amountOfSecuritiesSold>
        <grossProceeds>3276000</grossProceeds>
      </securitiesSoldInPast3Months>
      <remarks>The securities to be sold were acquired from grant vests during the period of 06/01/10 through 11/01/10</remarks>
      <noticeSignature>
        <noticeDate>06/14/2024</noticeDate>
        <signature>/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for David Schaeffer</signature>
      </noticeSignature>
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text: 144
  0001166976
  XXXXXXXX
  LIVE
  0001158324
  Cogent Communications Holdings, Inc.
  000-51829
  2450 N.  Street  N.W.
  Washington
  DC
  20037
  202-295-4200
  David Schaeffer
  Founder
  CEO
  Common Stock
  J.P. Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  60000
  3087000
  49024447
  06/14/2024
  NASDAQ
  Common Stock
  06/01/2010
  Grant Vest
  Issuer
  N
  60000
  11/01/2010
  Compensation
  N
  David Schaeffer
  C/o Cogent Communications Holdings Inc
  2450 N. Street N.W.
  Washington
  DC
  20037
  Common Stock
  03/15/2024
  26174
  1680633
  David Schaeffer
  C/o Cogent Communications Holdings Inc
  2450 N. Street N.W.
  Washington
  DC
  20037
  Common Stock
  05/13/2024
  50000
  2972000
  David Schaeffer
  C/o Cogent Communications Holdings Inc
  2450 N. Street N.W.
  Washington
  DC
  20037
  Common Stock
  06/12/2024
  60000
  3276000
  The securities to be sold were acquired from grant vests during the period of 06/01/10 through 11/01/10
  06/14/2024
  /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for David Schaeffer