| Marcus CS - Beeline Gas Systems | Compressor station | NM | Beeline Gas Systems | |
| Marion Gas Plant | Gas processing plant | Osceola County, MI | Dart Oil & Gas Corp | In service |
| Mark Merritt Gas Plant | Gas processing plant | Andrews County, TX | | |
| Markham | Underground storage | Matagorda County, TX | Tres Palacios Gas Storage LLC | In service |
| Markham Gas Process PLT | Gas processing plant | Matagorda County, TX | | |
| Markham Gas Processing Plant | Gas processing plant | Matagorda County, TX | Williams Field Services - Gulf Coast Company | In service |
| Markle Storage | Underground storage | Jefferson County, PA | National Fuel Gas Supply Corporation | In service |
| Markley Plant | Gas processing plant | Jack & Young County, TX | W. W. Sub, Inc. | In service |
| Markwest CDP Compressor Station | Compressor station | Hughes County, OK | Petrolink Energy LLC | |
| Markwest Cobb Extraction | Gas processing plant | Kanawha County, WV | Markwest Energy Partners, L.P. | In service |
| Markwest Liberty Midstream & Resources Llc/joe Cain L/r Site | Gas processing plant | Washington County, PA | Markwest Liberty Midstream & Resources, LLC | |
| Markwest Liberty Midstream & Resources Llc/wilhelm L/r Site | Gas processing plant | Washington County, PA | Markwest Liberty Midstream & Resources, LLC | |
| Markwest Liberty Midstream & Resources/huntington Farms L/r | Gas processing plant | Washington County, PA | Markwest Liberty Midstream & Resources, LLC | |
| Markwest Oklahoma Gas Custer Compressor Station | Compressor station | Custer County, OK | Markwest Oklahoma Gas Company, LLC | |
| Markwest Oklahoma Gas Dorothy Compressor Station | Compressor station | Kingfisher County, OK | Markwest Oklahoma Gas Company, LLC | |
| Markwest Oklahoma Gas Hammon Compressor Station | Compressor station | Custer County, OK | Markwest Oklahoma Gas Company, LLC | |
| Markwest Oklahoma Gas Lamar Compressor Station | Compressor station | Hughes County, OK | Markwest Oklahoma Gas Company, LLC | |
| Markwest Oklahoma Gas Loyal Compressor Station | Compressor station | Kingfisher County, OK | Markwest Oklahoma Gas Company, LLC | |
| Markwest Oklahoma Gas Meyer Compressor Station | Compressor station | Dewey County, OK | Markwest Oklahoma Gas Company, LLC | |
| Marlan Gas Plant | Gas processing plant | NM | Summit Midstream Permian, LLC | |
| Marlow Chemical Blending Plant | Gas processing plant | Stephens County, OK | Flotek Chemistry LLC | |
| Marmarth Gas Plant | Gas processing plant | Slope County, ND | ONEOK Inc. | |
| Marmath | Gas processing plant | ND | ONEOK Inc. | |
| Marsh Compressor Station | Compressor station | Pottawatomie County, OK | Petrolink Energy LLC | |
| Martin Energy Services Amelia terminal | Terminal | LA | Martin Energy Services LLC | |
| Martin Energy Services Blakeley Island terminal | Terminal | AL | Martin Energy Services LLC | |
| Martin Energy Services Fourchon 15 terminal | Terminal | LA | Martin Energy Services LLC | |
| Martin Energy Services Fourchon 16 terminal | Terminal | LA | Martin Energy Services LLC | |
| Martin Energy Services Galveston - Pelican Island Terminal | Terminal | TX | Martin Energy Services LLC | |
| Martin Energy Services Harbor Island Terminal | Terminal | TX | Martin Energy Services LLC | |
| Martin Energy Services Lake Charles Dock terminal | Terminal | LA | Martin Energy Services LLC | |
| Martin Energy Services Marine 193 Dock terminal | Terminal | LA | Martin Energy Services LLC | |
| Martin Energy Services Pascagoula terminal | Terminal | MS | Martin Energy Services LLC | |
| Martin Energy Services Port Arthur Dock terminal | Terminal | TX | Martin Energy Services LLC | |
| Martin Energy Services Theodore terminal | Terminal | AL | Martin Energy Services LLC | |
| Martin Midstream Tampa terminal | Terminal | FL | Martin Midstream Partnership LP | |
| Martin Operating Neches terminal | Terminal | TX | Martin Operating Partnership, L.p. | |
| Martin Operating Stanolind terminal | Terminal | TX | Martin Operating Partnership, L.p. | |
| Martinez Terminal | Terminal | CA | Martinez Terminal Company LLC | |
| Martinsville Plant | Gas processing plant | Nacogdoches County, TX | | |
| Mary Ann Compressor Station | Compressor station | Washita County, OK | Cascade Pipeline | |
| Marysville Storage System | Underground storage | St. Clair County, MI | Semco Energy Gas Company | In service |
| Marysville terminal | Terminal | MI | Marysville Hydrocarbons LLC | |
| Masden Gas Com 1e CDP | Compressor station | NM | Hilcorp Energy Company | |
| Matchbox Compressor Station | Compressor station | NM | Eog Resources Inc | |
| Mathews Compressor Station | Compressor station | Carter County, OK | Targa Pipeline Midcontinent LLC | |
| Matli Plant | Gas processing plant | Blaine County, OK | Kinder Morgan, Petrolink Energy LLC | In service |
| Maverick Terminals Corpus LLC | Terminal | TX | Maverick Terminals Corpus, LLC | |
| Maxwell Compressor Station | Compressor station | Stephens County, OK | Targa Pipeline Midcontinent LLC | |
| Mayer Compressor Station | Compressor station | Coal County, OK | Mla Midstream LLC | |