<?xml version="1.0" encoding="US-ASCII"?>
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->
<!-- Created: Thu Mar 26 12:00:19 UTC 2026 -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <roleRef xlink:type="simple" xlink:href="dtm-20260505.xsd#dtm_r_AdditionalDimensions" roleURI="http://dtmidstream.com/role/AdditionalDimensions"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
<!-- [WMV6][Pl5GKXoQ59Wqc/ZPk4Nk/Ou+8YUuN9aJw9TzgzA0zEmMo0F4CCJlQASoimYCjxHz1HlM4ogdy2Vu4Md0pJFhfCc5R8e44qXRb+dqr38Misej8i1Lb+Vb1RhnbtJhmBw7A7g/mEFI+UPQfPt15mv0LewvKfTMnhBHER00VW+BrhsCLiDjmUpMfXl1wZ5Iu5s9NLLhfTa/aCHMZ9B0sjfX9FHdqWbKXJWvnO2WRXjIANFHfN646On22lruY2X8X2O2OP64mfEKS9MhJ8Ilt1QAMhHP+QbPW0N09QPc1SPxVTchk2c09JbOsvYh9MI8J3rtHMrxzRLDItGTwR9+BHtmEBT6C9P1S1pk2sZLNUWAyXSdv1BQ/mU=] CSR-->
  <definitionLink xlink:role="http://dtmidstream.com/role/AdditionalDimensions" xlink:type="extended"/>
</linkbase>
