| 1 | H & H Star Energy Inc | Traverse City, MI 49684 | Oil & Gas Operator | Aug 2016 |
| 2 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 3 | H & R Oil Company | | Oil & Gas Operator | Dec 2000 |
| 4 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 5 | H C M Energy LLC | Billings, MT 59102 | Oil Operator | Jul 2003 |
| 6 | H D Oil Company | Thermopolis, WY 82443 | Oil Operator | Aug 2025 |
| 7 | H G H Oil Company | | Oil Operator | Dec 1990 |
| 8 | H2oil Services LLC | | Oil Operator | Aug 2025 |
| 9 | Hadley/Jackson Energy LLC | Lake Forest, IL 60045 | Oil & Gas Operator | Aug 2025 |
| 10 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 11 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 12 | Hallwood Petroleum | Denver, CO 80237 | Oil & Gas Operator | Dec 1997 |
| 13 | Hamon Jake L | Dallas, TX 75201-3902 | Oil & Gas Operator | Nov 1997 |
| 14 | Hanson Operating Company Inc | Roswell, NM 88202 | Oil & Gas Operator | Jul 2025 |
| 15 | Harpel John P Jr | FT. Collins, CO 80525 | Oil & Gas Operator | May 1998 |
| 16 | Harper Oil Co. | Denver, CO 80217 | Oil & Gas Operator | Jun 2025 |
| 17 | Harrell Oil Company LLC | Ardmore, OK 73402 | Oil Operator | Jan 2025 |
| 18 | Harvey E Yates Company | Roswell, NM 88202 | Oil & Gas Operator | Feb 2015 |
| 19 | Haug Lawrence | Kimball, NE 69145 | Oil & Gas Operator | Jul 2007 |
| 20 | Havoco Inc | Newcastle, WY 82701 | Oil & Gas Operator | Aug 2005 |
| 21 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 22 | Hawks Industries Inc | Casper, WY 82601 | Oil & Gas Operator | Jun 1993 |
| 23 | Hay Leonard | Rock Springs, WY 82901 | Oil & Gas Operator | Sep 1994 |
| 24 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 25 | Heartland Energy Company | Big Horn, WY 82833 | Gas Operator | Jun 2012 |
| 26 | Hedges Spencer | Casper, WY 82604 | Oil Operator | Mar 2024 |
| 27 | Helena Resources Inc | Lakewood, CO 80215 | Oil & Gas Operator | Jul 2025 |
| 28 | Helis Oil & Gas Company LLC Estate | New Orleans, LA 70130 | Oil & Gas Operator | Jul 2022 |
| 29 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 30 | Herbaly Petroleum Corp | FT Worth, TX 76102 | Oil & Gas Operator | Feb 2002 |
| 31 | Hershey Oil Corporation | | Oil & Gas Operator | Jul 1992 |
| 32 | Hesperus Energy II LLC | | Oil Operator | Jul 2025 |
| 33 | Hi-Pro Production | Gillette, WY 82717 | Gas Operator | Nov 2003 |
| 34 | High Plains Gas LLC | Gillette, WY 82717 | Gas Operator | Aug 2014 |
| 35 | High Summit Oil & Gas Inc | | Oil & Gas Operator | Sep 1987 |
| 36 | Highland Exploration | | Oil Operator | Sep 1979 |
| 37 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 38 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 39 | HMX Investments, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2025 |
| 40 | HNG Oil Company | | Oil & Gas Operator | Jun 1987 |
| 41 | Hodge T F | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2007 |
| 42 | Hoff Elmer & Mildred | | Oil & Gas Operator | Jan 1991 |
| 43 | Holden Harold B | Billings, MT 59103 | Oil Operator | Jun 1996 |
| 44 | Holly Energy Inc | | Oil Operator | Apr 1983 |
| 45 | Holwell Drilling Company | | Oil Operator | Sep 1992 |
| 46 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 47 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 48 | Hot Springs Resources LTD | Casper, WY 82601 | Oil Operator | Dec 2014 |
| 49 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 50 | Hovivian Gregory E | La Crescenta, CA 91214 | Gas Operator | Dec 1999 |
| 51 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 52 | HR Energy LLC | Shelby, MT 59474 | Oil & Gas Operator | Jul 2025 |
| 53 | HRM Resources II, LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 54 | HRM Resources III LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2022 |
| 55 | HRM Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2015 |
| 56 | Hrubetz Oil Co. | Dallas, TX 75225 | Oil Operator | Sep 1986 |
| 57 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 58 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Oct 2025 |
| 59 | Hudson Group LLC | Casper, WY 82601 | Oil & Gas Operator | Jul 2025 |
| 60 | Hughes Oil Company Inc | Odessa, TX 79765 | Oil & Gas Operator | Feb 2004 |
| 61 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 62 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 63 | Hunt Petroleum (Aec), Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 64 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 65 | Hurley Oil Company | | Oil Operator | Dec 1988 |
| 66 | Husky Oil Company | Cody, WY 82414 | Oil & Gas Operator | Dec 1984 |
| 67 | Hyco Oil Inc | Newcastle, WY 82701 | Oil & Gas Operator | Dec 2006 |
| 68 | Hydrocarbon Management, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 1996 |
| 69 | Hyland Oil Corporation | | Oil & Gas Operator | Apr 1990 |
| 70 | Hyperion Oil & Gas LLC | Dallas, TX 75251 | Oil & Gas Operator | Oct 2025 |