| 601 | Jade Resources Inc | Englewood, CO 80112 | Oil Operator | Jul 1998 |
| 602 | Jay Management Company LLC | Houston, TX 77057 | Oil & Gas Operator | Sep 2026 |
| 603 | Jayne Morton Living Trust | Troup, TX 75789 | Oil Operator | Jul 2023 |
| 604 | Jed Oil USA Inc | | Oil & Gas Operator | Dec 2008 |
| 605 | Jellco LLC | Thermopolis, WY 82443 | Oil Operator | Jul 2026 |
| 606 | Jenex Petroleum Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2026 |
| 607 | Jetta Operating Company, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2026 |
| 608 | Jims Water Service Inc | Gillette, WY 82717 | Oil & Gas Operator | Oct 2016 |
| 609 | JM Cox Resources LP | Midland, TX 79702 | Oil & Gas Operator | Apr 2019 |
| 610 | JN Exploration & Production | Billings, MT 59103-0159 | Oil & Gas Operator | Apr 2001 |
| 611 | Joemar Wyoming Operating LLC | | Oil & Gas Operator | Jul 2026 |
| 612 | Jogruss Oil Corporation | | Oil & Gas Operator | Jul 1991 |
| 613 | Jonah Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2026 |
| 614 | JP Oil Wyoming LLC | Lafayette, LA 70505 | Oil & Gas Operator | Jun 2026 |
| 615 | JT Operating LLC | Douglas, WY 82633 | Oil & Gas Operator | Jul 2026 |
| 616 | Julander Energy Company | Denver, CO 80614 | Oil Operator | Apr 2016 |
| 617 | Julius Roy G | Wichita, KS 67206 | Oil & Gas Operator | Jun 2026 |
| 618 | Juniper Petroleum Corporation | | Oil & Gas Operator | Aug 1983 |
| 619 | Justice Oil & Gas LLC | Gillette, WY 82716 | Oil & Gas Operator | Jul 2026 |
| 620 | Jva Operating Company | Midland, TX 79710 | Oil & Gas Operator | Oct 2021 |
| 621 | K & W Oil Company | MT Carmel, IL 62830 | Oil & Gas Operator | May 2013 |
| 622 | K N Energy Inc | Lakewood, CO 80228 | Oil & Gas Operator | Nov 2000 |
| 623 | Kachina Exploration Inc | Cheyenne, WY 82003 | Oil & Gas Operator | Jul 2000 |
| 624 | Kaiser Energy Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 1990 |
| 625 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Sep 2026 |
| 626 | Kamco Limited | Salt Lake City, UT 84105 | Oil Operator | Sep 2016 |
| 627 | Kaneb Oil & Gas | | Oil & Gas Operator | Oct 1987 |
| 628 | Kant Walter F | Lance Creek, WY 82222 | Oil & Gas Operator | Dec 2002 |
| 629 | Kara Enterprises Inc | Upton, WY 82730 | Oil Operator | Jul 2013 |
| 630 | Karlton Terry Oil Company | | Oil Operator | Jan 1991 |
| 631 | Kase Energy LLC | Roseville, MN 55113 | Oil Operator | Aug 2006 |
| 632 | Katherman Vance E | Casper, WY 82601 | Oil Operator | Dec 2004 |
| 633 | Kauffman K P Company Inc | Denver, CO 80202 | Oil & Gas Operator | Mar 1996 |
| 634 | KC Resources Inc | Snowmass VLG., CO 81615 | Oil & Gas Operator | May 2026 |
| 635 | KCS Medallion Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Nov 2018 |
| 636 | KCS Mountain Resources Inc | Manderson, WY 82432 | Oil & Gas Operator | Nov 2006 |
| 637 | Keas Production Company LLC | Estes Park, CO 80517 | Oil Operator | Jul 2026 |
| 638 | Keba Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2015 |
| 639 | Kedco Management Corp | | Oil & Gas Operator | Jul 1985 |
| 640 | Keith Walker O & G Co LLC | | Oil Operator | Aug 2026 |
| 641 | Keiths Pumping Service | Douglas, WY 82633 | Oil & Gas Operator | Aug 2003 |
| 642 | Kelly Operating Company | | Oil & Gas Operator | Oct 1991 |
| 643 | Kem Ventures, LP | Katy, TX 77450 | Oil & Gas Operator | Jul 2026 |
| 644 | Kemmerer Coal Co | | Oil & Gas Operator | Dec 1981 |
| 645 | Kenai Oil & Gas Inc | | Oil & Gas Operator | Jun 1987 |
| 646 | Kennedy & Mitchell | Woodward, OK 73802 | Oil & Gas Operator | Dec 1988 |
| 647 | Kennedy George C | Upton, WY 82730 | Oil & Gas Operator | Oct 2018 |
| 648 | Kennedy Oil | Gillette, WY 82716 | Oil & Gas Operator | Jul 2026 |
| 649 | Kentex Worland LLC | Dallas, TX 75225 | Oil & Gas Operator | Sep 2025 |
| 650 | Kentex Worland Operating Co LLC | | Oil & Gas Operator | Jun 2026 |
| 651 | Kentta & Drwenski | Casper, WY 82602 | Oil & Gas Operator | Nov 1995 |
| 652 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Jul 2026 |
| 653 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Sep 2026 |
| 654 | Kerr-McGee Rocky Mountain Corp | Denver, CO 80202 | Oil & Gas Operator | Jan 2007 |
| 655 | Kerry Petroleum Co Inc | Midland, TX 79708 | Oil & Gas Operator | Jun 2010 |
| 656 | Kestrel Energy Inc | Lakewood, CO 80401 | Oil & Gas Operator | Jan 2008 |
| 657 | Kewanee Oil Company | Houston, TX 77001 | Oil & Gas Operator | Aug 1978 |
| 658 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jun 2026 |
| 659 | Kiesling Oil Company | Osage, WY 82723 | Oil & Gas Operator | Oct 2007 |
| 660 | Kinder Morgan Inc | Lakewood, CO 80228 | Oil & Gas Operator | Dec 2011 |
| 661 | Kings Peak Energy LLC | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 662 | Kings X Oil Company LLC | Gillette, WY 82717 | Oil Operator | Aug 2016 |
| 663 | Kirkwood W C | Casper, WY 82602 | Oil & Gas Operator | May 2005 |
| 664 | Kiska Oil & Gas Inc | Tulsa, OK 74103 | Oil Operator | Oct 2012 |
| 665 | Kissack Resources. LLC | | Oil & Gas Operator | Jul 2026 |
| 666 | Kissack Water & Oil Service Inc | Rozet, WY 82727 | Oil & Gas Operator | Jul 2026 |
| 667 | Kissinger Petroleum Corp | | Oil & Gas Operator | Nov 1983 |
| 668 | Klabzuba Oil & Gas Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2012 |
| 669 | Kobar Corporation | Riverton, WY 82501 | Gas Operator | Dec 1996 |
| 670 | Koch Exploration Company | Houston, TX 77046 | Oil & Gas Operator | Apr 2003 |
| 671 | Koch Exploration Company, LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2019 |
| 672 | Koch Production Company | Worland, WY 82401 | Oil & Gas Operator | Dec 2002 |
| 673 | Kodiak Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2020 |
| 674 | Krejci Harry L | | Oil & Gas Operator | May 2026 |
| 675 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2026 |
| 676 | L & B Oil Company Inc | Houston, TX 77079 | Oil & Gas Operator | Mar 2025 |
| 677 | L & J Operating Inc | Gillette, WY 82718 | Oil & Gas Operator | Aug 2016 |
| 678 | L & R Drilling Company | Belle Fourche, SD 57717 | Oil & Gas Operator | Dec 1999 |
| 679 | L B Industries Inc | Englewood, CO 80112 | Oil & Gas Operator | Jun 2003 |
| 680 | L R Company | Casper, WY 82602 | Oil & Gas Operator | Sep 2007 |
| 681 | La Prele Exploration | | Oil & Gas Operator | Oct 1979 |
| 682 | Labarge Minerals Inc | Labarge, WY 83123 | Oil & Gas Operator | Jan 2020 |
| 683 | Ladd & Lukowicz | | Oil & Gas Operator | May 1983 |
| 684 | Lagniappe Interest Inc | Evergreen, CO 80439 | Oil & Gas Operator | Jun 2006 |
| 685 | Laguna Petroleum Company | Casper, WY 82601 | Oil & Gas Operator | Dec 1982 |
| 686 | Lakota Partnership | Denver, CO 80202 | Oil Operator | Oct 1990 |
| 687 | Lance Oil & Gas Company Inc | Kirtland, NM 87417 | Oil & Gas Operator | Mar 2013 |
| 688 | Langley Energy | Euless, TX 76040 | Gas Operator | Jan 2016 |
| 689 | Lappin Oil LLC | Douglas, WY 82633 | Oil & Gas Operator | Aug 2026 |
| 690 | Lario Oil & Gas Company | Denver, CO 80206 | Oil & Gas Operator | Sep 2026 |
| 691 | Lasmo Energy Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2024 |
| 692 | Lawson Oil Company | Buckeye, AR 85326 | Oil Operator | Mar 1996 |
| 693 | Lear Petroleum Exploration | | Oil & Gas Operator | Jul 2013 |
| 694 | Leclair-Westwood Inc | | Oil & Gas Operator | Mar 1982 |
| 695 | Leeman Don J | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 1998 |
| 696 | Legacy Energy Inc | Carpinteria, CA 93013 | Oil & Gas Operator | Jun 2012 |
| 697 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Sep 2026 |
| 698 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 699 | Lewis & Clark Exploration | | Oil Operator | Feb 1989 |
| 700 | Lewis Yale H | | Oil & Gas Operator | Aug 1986 |