| 601 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 602 | Hawks Industries Inc | Casper, WY 82601 | Oil & Gas Operator | Jun 1993 |
| 603 | Hawkwood Energy Operating, LLC | Houston, TX 77224 | Oil & Gas Operator | Apr 2022 |
| 604 | Hawley & Desimon | Conrad, MT 59425 | Oil Operator | Mar 2026 |
| 605 | Hawley Hydrocarbons, Merrill&Carol Hawley Dba | Great Falls, MT 59405 | Oil Operator | Mar 2026 |
| 606 | Hawley Oil Company | Great Falls, MT 59405-5156 | Oil Operator | Dec 2025 |
| 607 | Hawn Bros. & Venus Oil Co. | Corpus Christ, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 608 | Hawn Brothers | Corpus Christ, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 609 | Hawn Brothers Company | Corpus Christ, TX 78401 | Oil & Gas Operator | Jan 2003 |
| 610 | Hawn Petroleum I | | Oil Operator | Jun 1989 |
| 611 | Hawthorn Energy Partners, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2026 |
| 612 | Hawthorne Carl A | Mounds, OK 74047-4936 | Oil & Gas Operator | Apr 2015 |
| 613 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 614 | Hawthorne-Tipco | | Oil & Gas Operator | Oct 1978 |
| 615 | Hay Creek Investments, L.L.C. | Santa Anna, TX 76878 | Oil Operator | Jul 2018 |
| 616 | Hay Exploration, Inc | Ashland, KY 41102 | Oil & Gas Operator | Dec 2024 |
| 617 | Hay Leonard | Rock Springs, WY 82901 | Oil & Gas Operator | Sep 1994 |
| 618 | Hayabusa Energy USA, LLC | Pampa, TX 79065 | Oil & Gas Operator | Jun 2026 |
| 619 | Hayden Harper Energy Ka, LLC | Charlotte, NC 28203-4173 | Oil & Gas Operator | Dec 2021 |
| 620 | Hayden Operating | | Oil & Gas Operator | Feb 2026 |
| 621 | Hayden, Mabel | Barkerton, KY 42717 | Oil Operator | Dec 2015 |
| 622 | Haydens Oil And Gas LLC | Dover, OK 73734 | Oil & Gas Operator | Feb 2026 |
| 623 | Hayes & Assoc Inc | | Oil & Gas Operator | Oct 1991 |
| 624 | Hayes & Hudson | Bartlesville, OK 74003 | Oil & Gas Operator | Mar 2026 |
| 625 | Hayes James Brent | Guysville, OH 45735-9496 | Oil & Gas Operator | Dec 2025 |
| 626 | Hayes Oil & Gas Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2003 |
| 627 | Hayes Oil & Gas LLC | Attica, KS 67009 | Oil & Gas Operator | Feb 2026 |
| 628 | Hayes, Marshall A. III | Chilton, TX 76632 | Oil & Gas Operator | Jun 2026 |
| 629 | Haylan Oil Company | Midland, TX 79710 | Oil & Gas Operator | Jan 2000 |
| 630 | Haylandia, LLC | Bloomfield, NY 14469 | Gas Operator | Dec 2024 |
| 631 | Haynes & Shirley Production Co. | Iowa Park, TX 76367 | Oil & Gas Operator | Jun 2026 |
| 632 | Haynes Jim L & Betty L | Haskell, OK 74436-8803 | Oil & Gas Operator | Dec 2013 |
| 633 | Haynes Production Company, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Dec 2006 |
| 634 | Haynie Drilling Co. Inc. | Corsicana, TX 75151 | Oil & Gas Operator | Dec 2011 |
| 635 | Haynie Energy Services LLC | Wortham, TX 76693 | Oil Operator | Jun 2026 |
| 636 | Haynie Robert L | | Gas Operator | Jan 2004 |
| 637 | Hays & Boydston | Graham, TX 76450 | Oil & Gas Operator | Mar 1994 |
| 638 | Hays & Croker Partnership | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 639 | Hays Herb E & K S | Bartlesville, OK 74006 | Oil Operator | Feb 2026 |
| 640 | Hays Oil Field S | | Oil Operator | Nov 1988 |
| 641 | Hays Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2000 |
| 642 | Hays Partnership | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 643 | Hays Production LLC | Velma, OK 73491 | Oil & Gas Operator | Mar 2026 |
| 644 | Hays Stanley L | Wynola, OK 74084 | Oil Operator | May 2022 |
| 645 | Hays, David H. | Olney, TX 76374 | Oil & Gas Operator | Dec 1995 |
| 646 | Hays, John H. | Graham, TX 76450 | Oil & Gas Operator | Jun 2026 |
| 647 | Hays, Mrs. Earl (Cora) | Big Spring, TX 79720 | Oil & Gas Operator | Apr 2005 |
| 648 | Hays, T.G. Petroleum Expl., Inc. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Dec 1994 |
| 649 | Haywood, Paul M. Jr. | Denton, TX 76206 | Oil & Gas Operator | Mar 2002 |
| 650 | Hazelett Oil Company, Inc. | Dale, TX 78616 | Oil & Gas Operator | Sep 2005 |
| 651 | Hazelett Oil, Inc. | Dale, TX 78616 | Oil & Gas Operator | Aug 2024 |
| 652 | Hazelwood Louis J | Albuquerque, NM 87111-6870 | Oil & Gas Operator | Feb 2023 |
| 653 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Feb 2026 |
| 654 | Hazen Oil Company | Cleveland, OK 74020-9633 | Oil Operator | Jul 2020 |
| 655 | Hazen, Paul D. | Great Bend, KS 67530 | Oil Operator | Nov 1990 |
| 656 | Hazen, Ty Anthony | Lyons, KS 67554 | Oil Operator | Feb 2026 |
| 657 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 658 | Hazoco, L.L.C. | Bellville, TX 77418 | Oil Operator | Jun 2026 |
| 659 | HB Energy LLC | Wellsville, KS 66092 | Oil Operator | Feb 2026 |
| 660 | HB Oil Company | Abilene, TX 79602 | Oil & Gas Operator | Jun 2023 |
| 661 | HBC Oil Company, LLC | San Antonio, TX 78266 | Oil Operator | Jun 2026 |
| 662 | HC Resources, Inc. | | Oil & Gas Operator | Jul 2011 |
| 663 | Hce Operating LLC | Smyer, TX 79367 | Oil & Gas Operator | Jun 2026 |
| 664 | HCG Energy Corporation & Subs | | Oil & Gas Operator | Mar 2015 |
| 665 | HCL Inc | Woodward, OK 73802-1074 | Oil Operator | Mar 2015 |
| 666 | HCM | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 667 | HCW Exploration, Inc. | | Oil & Gas Operator | Jun 1986 |
| 668 | HD Special-Situations, LP | San Francisco, CA 94111 | Oil & Gas Operator | Feb 2014 |
| 669 | HD Well Services LLC | Wellsville, KS 66092 | Oil Operator | Feb 2026 |
| 670 | HDH Resources, Inc. | Wilmore, KS 67155 | Oil & Gas Operator | Oct 2025 |
| 671 | HDS Production | | Oil Operator | Mar 1998 |
| 672 | HDT Inc. | | Oil & Gas Operator | Mar 2026 |
| 673 | Headington Canada Corp. | Dallas, TX 75231 | Gas Operator | Jun 2000 |
| 674 | Headington Energy Corporation | | Oil & Gas Operator | Aug 1992 |
| 675 | Headington Energy Partners, LLC | Corpus Christ, TX 78401 | Oil & Gas Operator | Jun 2026 |
| 676 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 677 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 678 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 679 | Headline Resources, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Aug 1997 |
| 680 | Headwaters Energy Partners, LLC | Dripping SPGS, TX 78620 | Oil & Gas Operator | Jun 2026 |
| 681 | Headwaters Oil Company | | Oil & Gas Operator | Oct 1981 |
| 682 | Heape Exploration, Inc. | Dallas, TX 75367 | Oil & Gas Operator | Dec 2020 |
| 683 | Heape, Gene G. | Dallas, TX 75367 | Oil & Gas Operator | Jun 2003 |
| 684 | Hearn Oil Co. LLC | Newport, OH 45768 | Oil & Gas Operator | Dec 2024 |
| 685 | Heart Land Petroleum Corporation | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 686 | Heartland Energy Company | Big Horn, WY 82833 | Gas Operator | Jun 2012 |
| 687 | Heartland Enterprises, Incorporated | Phillipsburg, KS 67661 | Oil Operator | May 2005 |
| 688 | Heartland Environmental Services | Watonga, OK 73080 | Oil & Gas Operator | May 1999 |
| 689 | Heartland Exploration | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2000 |
| 690 | Heartland Exploration Inc | Edmond, OK 73013 | Oil & Gas Operator | Dec 2015 |
| 691 | Heartland Oil & Gas Inc. | Gypsum, KS 67448 | Gas Operator | Jun 2011 |
| 692 | Heartland Production, Inc. | Cuero, TX 77954 | Oil & Gas Operator | Jun 2026 |
| 693 | Heartland Pumping | Hennessey, OK 73742-7311 | Oil & Gas Operator | Feb 2026 |
| 694 | Heartland Resources, Inc. | Temple, TX 76501 | Oil & Gas Operator | Mar 2008 |
| 695 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 696 | Heat Can Oil, LLC | Chanute, KS 66720 | Oil Operator | Jun 2009 |
| 697 | Heat Controller Inc | Jackson, MI 49204 | Oil & Gas Operator | Dec 1996 |
| 698 | Heat Waves Hot Oil Service LLC | Denver, CO 80202 | Oil Operator | Jun 2011 |
| 699 | Heath Jack A | Tulsa, OK 74132-2403 | Oil & Gas Operator | Jan 2013 |
| 700 | Heath Oil Co., Inc. | Washington, OK 73093-4702 | Oil & Gas Operator | Feb 2026 |