| 501 | MCQ Natural Gas Co Inc | Leechburg, PA 15656-0594 | Gas Operator | Dec 2012 |
| 502 | MDS Energy Dev LLC | Kittanning, PA 16201-4403 | Oil & Gas Operator | Nov 2025 |
| 503 | MDS Energy LTD | Kittanning, PA 16201-4403 | Gas Operator | Feb 2015 |
| 504 | Mead Oil LLC | Sheffield, PA 16347-1022 | Oil & Gas Operator | Dec 2024 |
| 505 | Medina Res Dev Co LLC | Cambridge Springs, PA 16403-3447 | Oil & Gas Operator | Sep 2025 |
| 506 | Meridian Exploration Corp. | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2021 |
| 507 | Meridian Oil & Gas Enterprises Inc | Blairsville, PA 15717-0337 | Oil & Gas Operator | Dec 2003 |
| 508 | Mervin Troyer | Union City, PA 16438-8510 | Gas Operator | Dec 2008 |
| 509 | Mid Amer Natural Resources Inc | Erie, PA 16505-4760 | Gas Operator | Dec 1994 |
| 510 | Mid East Oil Co | Indiana, PA 15701-5378 | Gas Operator | Dec 2006 |
| 511 | Mid-Penn Energy Corporation | Harrisburg, PA 17101-1002 | Gas Operator | Dec 2021 |
| 512 | Mieka LLC | Flower Mound, TX 75028-7446 | Oil & Gas Operator | Dec 2014 |
| 513 | Millennium Oil & Gas Inc | Dexter, KS 67038 | Oil & Gas Operator | Dec 2024 |
| 514 | Minard Run Oil Co | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 515 | Minteer & Baker Gas Enterprise | Kittanning, PA 16201-5022 | Gas Operator | Dec 2024 |
| 516 | Minter Lee M | Bradford, PA 16701-3763 | Gas Operator | Dec 1991 |
| 517 | Missing Moon Oil Inc | Knox, PA 16232-4507 | Oil & Gas Operator | Dec 2024 |
| 518 | Mitch Well Energy Inc | Waterford, PA 16441-8143 | Oil & Gas Operator | Dec 2012 |
| 519 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 520 | Mob Corp | Waynesburg, PA 15370-2036 | Gas Operator | Dec 2007 |
| 521 | Monona LLC | Ligonier, PA 15658-0612 | Gas Operator | Nov 2025 |
| 522 | Monroe Res LTD | Fairport, NY 14450-3218 | Gas Operator | Dec 2004 |
| 523 | Mount Chestnut Dev LLC | Butler, PA 16002-3940 | Gas Operator | Dec 2017 |
| 524 | MSL Oil & Gas Corp | Bradford, PA 16701-0151 | Oil & Gas Operator | Dec 2024 |
| 525 | MT Savage Refractories | Pittsburgh, PA 15206-0171 | Gas Operator | Dec 2021 |
| 526 | MTN Energy | Aleppo, PA 15310 | Oil & Gas Operator | Nov 2025 |
| 527 | MTN V Oil & Gas Inc | Indiana, PA 15701-8914 | Oil & Gas Operator | Nov 2025 |
| 528 | Murphy Prod Inc | Vanderbilt, PA 15486-1001 | Oil & Gas Operator | Dec 2024 |
| 529 | Mutual Oil & Gas Co | Akron, OH 44311 | Oil & Gas Operator | Dec 2000 |
| 530 | Natl Fuel Gas Supply Corp | Williamsville, NY 14221-5887 | Oil & Gas Operator | Dec 2009 |
| 531 | Natural Energy Dev Corp | Pittsburgh, PA 15241-1548 | Oil & Gas Operator | Dec 2018 |
| 532 | Natural Oil & Gas Corp | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |
| 533 | NCL Natural Resources LLC | Spring, TX 77381-5261 | Oil & Gas Operator | Dec 2017 |
| 534 | Nea Cross Inc | Erie, PA 16508-2769 | Gas Operator | Dec 1991 |
| 535 | New Century Energy Inc | MC Donald, PA 15057-2163 | Oil & Gas Operator | Dec 2021 |
| 536 | New York Natural Gas Corp | Pittsburgh, PA 15222-1402 | Gas Operator | Dec 1990 |
| 537 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Dec 2025 |
| 538 | Norbert J Baumgart | Warren, PA 16365-3403 | Oil & Gas Operator | Dec 2009 |
| 539 | Nornew Inc | Houston, TX 77063-2140 | Oil & Gas Operator | Dec 2008 |
| 540 | North Amer Oil & Gas Drilling Co Inc | Pleasantville, PA 16341-0197 | Oil Operator | Dec 1999 |
| 541 | North Cambria Fuel Co | Blairsville, PA 15717-7961 | Gas Operator | Dec 2008 |
| 542 | North East Gas & Oil Co | Scottsville, VA 24590-3962 | Oil & Gas Operator | Dec 2013 |
| 543 | North John M | Valatie, NY 12184-5005 | Gas Operator | Dec 2014 |
| 544 | North Penn Gas Co | Allentown, PA 18101-1139 | Gas Operator | Dec 2000 |
| 545 | North Star Energy Resources LLC | Waynesburg, PA 15370-3833 | Gas Operator | Dec 2024 |
| 546 | Northeast Natural Energy LLC | Charleston, WV 25301-2719 | Oil & Gas Operator | Nov 2025 |
| 547 | Northeastern Opr Co Inc | Shelocta, PA 15774-2346 | Gas Operator | Dec 2024 |
| 548 | Northwest Natural Gas Co | Albion, PA 16401-9998 | Oil & Gas Operator | Dec 1990 |
| 549 | Northwestern Inc | East Brady, PA 16028 | Gas Operator | Dec 2012 |
| 550 | Noumenon Corporation | Core, WV 26541-7072 | Oil & Gas Operator | Dec 2024 |
| 551 | NTS Energy LLC | Indiana, PA 15701-1801 | Oil & Gas Operator | Dec 2015 |
| 552 | Nucomer Energy LLC | Erie, PA 16510 | Oil & Gas Operator | Nov 2025 |
| 553 | Nys Natural Gas Co | Englewood, CO 80111-4737 | Gas Operator | Dec 1984 |
| 554 | Nytis Exploration Company LLC | Lexington, KY 40509 | Oil & Gas Operator | Dec 2021 |
| 555 | Oakes Gas Co Inc | Kane, PA 16735-3905 | Gas Operator | Dec 2023 |
| 556 | Oakmont CC | Oakmont, PA 15139-1135 | Gas Operator | Dec 2024 |
| 557 | Ohio Kentucky Oil Corporation | Lexington, KY 40503 | Oil & Gas Operator | Dec 2023 |
| 558 | Oil & Gas MGMT Inc | Mount Pleasant, PA 15666-3304 | Oil & Gas Operator | Dec 2024 |
| 559 | Oil & Gas SVC Inc | Reelsville, IN 46171-9686 | Gas Operator | Dec 1991 |
| 560 | Old MTN Gas Co Inc | Pleasantville, PA 16341-0329 | Oil & Gas Operator | Dec 2020 |
| 561 | Olympus Energy, LLC | Canonsburg, PA 15317-7536 | Gas Operator | Jun 2025 |
| 562 | Olympus Prop Inc | Franklin Park, IL 60131-1418 | Oil & Gas Operator | Dec 1997 |
| 563 | Onexxx Prod & Exploration Corp | Jeannette, PA 15644-9691 | Gas Operator | Dec 2024 |
| 564 | Open Flow Gas Supply Corp | Du Bois, PA 15801-2442 | Oil & Gas Operator | Dec 2024 |
| 565 | Otter Exploration Inc | Warren, PA 16365-9689 | Oil & Gas Operator | Dec 2021 |
| 566 | Ows Acquisition Co LLC | Louisville, OH 44641 | Oil & Gas Operator | Dec 2024 |
| 567 | Ows Energy LLC | Carlton, PA 16311-1605 | Oil & Gas Operator | Nov 2025 |
| 568 | Oz Gas LTD | Tidioute, PA 16351-2648 | Oil & Gas Operator | Dec 2016 |
| 569 | P & C Energy Co | Allegany, NY 14706-9615 | Oil Operator | Dec 2015 |
| 570 | Pa DCNR State Parks Bur | Harrisburg, PA 17105-8551 | Gas Operator | Dec 2024 |
| 571 | Pa Dep Ofc Oil & Gas MGMT | Harrisburg, PA 17105-8765 | Gas Operator | Dec 1990 |
| 572 | Pa Gen Energy Co LLC | Warren, PA 16365-2510 | Oil & Gas Operator | Nov 2025 |
| 573 | Pa Gen Energy Corp | Warren, PA 16365-2510 | Oil & Gas Operator | Dec 2002 |
| 574 | Pa Land Holdings Corp | Waynesburg, PA 15370-3020 | Oil & Gas Operator | Dec 2011 |
| 575 | Pa Land Holdings LLC | Waynesburg, PA 15370-3020 | Gas Operator | Dec 2017 |
| 576 | Pa Mineral SVCS LLC | Indiana, PA 15701 | Oil & Gas Operator | Dec 2024 |
| 577 | Pa Prod SVC Inc | Indiana, PA 15701-0421 | Oil & Gas Operator | Dec 2024 |
| 578 | Pa State Sys Of Higher Ed Indiana Univ | Indiana, PA 15705-0001 | Gas Operator | Dec 2012 |
| 579 | Papesch Robert J | Waterford, PA 16441-4607 | Gas Operator | Dec 2024 |
| 580 | Parker & Parsley Dev LP | Irving, TX 75039-3745 | Oil & Gas Operator | Mar 2015 |
| 581 | Patalon Robert E | Erie, PA 16505-0444 | Gas Operator | Dec 2024 |
| 582 | Patrick Shipley | Indiana, PA 15701-6501 | Oil & Gas Operator | Dec 2016 |
| 583 | Patriot Exploration Corp | Stahlstown, PA 15687-1301 | Oil & Gas Operator | Dec 2024 |
| 584 | PDC Mountaineer LLC | Bridgeport, WV 26330-9665 | Oil & Gas Operator | Dec 2017 |
| 585 | Peak Energy LLC | Coffeyville, KS 67337 | Oil & Gas Operator | Sep 2025 |
| 586 | Pecora Enterprises | Bradford, PA 16701-1026 | Oil & Gas Operator | Dec 1999 |
| 587 | Peggy J Bell | Sheffield, PA 16347-0776 | Oil & Gas Operator | Dec 2004 |
| 588 | Pembrooke Oil & Gas Inc | Franklin, PA 16323-7760 | Oil & Gas Operator | Dec 2024 |
| 589 | Pemco Gas Inc | Indian Harbor B, FL 32937 | Oil & Gas Operator | Dec 1997 |
| 590 | Penn VIew Exploration Inc | Blairsville, PA 15717-7961 | Oil & Gas Operator | Dec 2024 |
| 591 | Penn VIrginia Oil & Gas Corp | Houston, TX 77024 | Oil & Gas Operator | Dec 2023 |
| 592 | Penneco Oil Company, Inc. | Delmont, PA 15626-2408 | Oil & Gas Operator | Dec 2024 |
| 593 | Pennenergy Resources LLC | Pittsburgh, PA 15275-1063 | Oil & Gas Operator | Nov 2025 |
| 594 | Pennfield Energy LLC | Erie, PA 16510-4760 | Oil & Gas Operator | Dec 2021 |
| 595 | Pennhills Resources LLC | MT. Jewett, PA 16740 | Oil & Gas Operator | Nov 2025 |
| 596 | Pennzoil Prod Co | Vienna, WV 26105-2141 | Oil & Gas Operator | Dec 2000 |
| 597 | Pentex Energy, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2003 |
| 598 | Peoples Gas Co LLC | Butler, PA 16001-4904 | Oil & Gas Operator | Dec 2005 |
| 599 | Peoples Natural Gas Co LLC | Pittsburgh, PA 15212 | Gas Operator | Dec 2016 |
| 600 | Petro Dev Corp | Bridgeport, WV 26330-0026 | Oil & Gas Operator | Dec 2013 |