| Middleberg Compressor Station | Compressor station | Grady County, OK | ET Gathering & Processing, LLC | |
| Midkiff Plant | Gas processing plant | Reagan County, TX | Targa Pipeline MC WestTex LLC | In service |
| Midland | Underground storage | Muhlenberg County, KY | Texas Gas Transmission, LLC | In service |
| Midline Compressor Station | Compressor station | Atoka County, OK | MarkWest Pioneer LLC | |
| Midmar East | Gas processing plant | Martin County, TX | Coronado Midstream LLC | In service |
| Midmar Gas Plant-West | Gas processing plant | Andrews County, TX | | |
| Midmar West | Gas processing plant | Andrews County, TX | Coronado Midstream LLC | In service |
| Midway | Underground storage | Spencer County, IN | Southern Indiana Gas & Electric Co | In service |
| Midway Compressor Station | Compressor station | Lincoln County, OK | Petrolink Energy LLC | |
| Midway Gas Plant | Gas processing plant | Crane County, TX | | |
| Midway-Extra | Underground storage | Putnam County, WV | Teavee Oil & Gas Inc | In service |
| Midwest Industrial Asphalt Lacrosse terminal | Terminal | WI | Midwest Industrial Asphalt Inc | |
| Midwest Marine River Rouge terminal | Terminal | MI | Midwest Marine Inc | |
| Milagro Cogeneration & Gas Plant | Gas processing plant | NM | Harvest Four Corners, LLC | |
| Milfay Compressor Station | Compressor station | Creek County, OK | Petrolink Energy LLC | |
| Milfay Plant | Gas processing plant | Creek County, OK | Kinder Morgan (Scissortail Energy LLC) | In service |
| Mill Creek North Plant Mine Plant 39 | Gas processing plant | Johnston County, OK | Us Silica CO | |
| Mill Creek Plant | Gas processing plant | Johnston County, OK | Mill Creek Dolomite | |
| Mill Creek South Plant Mill Plant 37 | Gas processing plant | Johnston County, OK | Us Silica CO | |
| Miller Compressor Station | Compressor station | Okmulgee County, OK | Enerfin Gathering-East LLC | |
| Mills | Underground storage | Gallatin County, IL | Egyptian Gas Storage Corp | In service |
| Milton Compressor Station | Compressor station | Le Flore County, OK | ET Gathering & Processing, LLC | |
| Milton Hub | Gas processing plant | Karnes County, TX | | |
| Minco Plant | Gas processing plant | Grady County, OK | Superior Midstream, LLC, Superior Pipeline Company L.l.c. | In service |
| Minden Gas Plant | Gas processing plant | Webster Parish, LA | ETC Field Services LLC | In service |
| Mineral City | Underground storage | Greene County, IN | Citizens Energy Group | In service |
| Misdtream Texas Ingleside Ingleside Facility terminal | Terminal | TX | Misdtream Texas Ingleside LLC | |
| Mission Rail Park | Terminal | TX | | |
| Mist | Underground storage | Columbia County, OR | NW Natural | In service |
| Mobile Bay | Gas processing plant | Mobile County, AL | DCP Operating Company, LP | In service |
| Mobile Crushing Portable Plant 1 | Gas processing plant | Bryan County, OK | Mobile Crushing Inc | |
| Mobley | Underground storage | Wetzel County, WV | Equitrans, L.P. | In service |
| Mobley Plant | Gas processing plant | Wetzel County, WV | Markwest Liberty Midstream & Res | In service |
| Mocane Compressor Station | Compressor station | Beaver County, OK | Colorado Interstate Gas Company, L.L.C. | |
| Mocane Station | Gas processing plant | Beaver County, OK | ET Gathering & Processing, LLC, ETC Field Services LLC | In service |
| Mockingbird Station | Compressor station | NM | Cotton Draw Midstream, LLC | |
| Moda Ingleside Energy Center terminal | Terminal | TX | Moda Ingleside LLC | |
| Monahans Terminal | Terminal | TX | | |
| Monitor 11 | Gas processing plant | Bay County, MI | Breitburn Operating LP | In service |
| Monroe City | Underground storage | Knox County, IN | Southern Indiana Gas & Electric Co | In service |
| Monroe Energy Chelsea terminal | Terminal | PA | Monroe Energy LLC | |
| Monroe Energy Philadelphia terminal | Terminal | PA | Monroe Energy LLC | |
| Monroe terminal | Terminal | LA | Monroe Terminal Company LLC | |
| Monroeville Plant | Gas processing plant | Monroe County, AL | Palmer Petroleum Inc | In service |
| Mont Belvieu Caverns LLC terminal | Terminal | TX | Mont Belvieu Caverns LLC | |
| Mont Belvieu Fractionation | Gas processing plant | Chambers County, TX | | |
| Mont Belvieu Fractionation Plant | Gas processing plant | Chambers County, TX | | |
| Mont Belvieu Fractionation Plant (Chambers County) | Gas processing plant | Chambers County, TX | | |
| Monument Gas Plant | Gas processing plant | NM | Targa Midstream Services LP | |
| Monument Plant | Gas processing plant | Lea County, NM | Targa Midstream Services LP | In service |