| 1 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 2 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 3 | Hardrock Oil Company | Great Falls, MT 59403 | Gas Operator | Aug 2025 |
| 4 | Hawkins, Robert S. | Kevin, MT 59454 | Oil Operator | Jun 2018 |
| 5 | Hawley & Desimon | Conrad, MT 59425 | Oil Operator | Jul 2025 |
| 6 | Hawley Hydrocarbons, Merrill&Carol Hawley Dba | Great Falls, MT 59405 | Oil Operator | Jul 2025 |
| 7 | Hawley Oil Company | Great Falls, MT 59405-5156 | Oil Operator | May 2025 |
| 8 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 9 | Helis Oil & Gas Company, L.L.C. | New Orleans, LA 70130 | Oil & Gas Operator | Oct 2023 |
| 10 | Herco Exploration LLC | Billings, MT 59103 | Gas Operator | Oct 2024 |
| 11 | Highline Exploration, Inc. | Tuscaloosa, AL 35402 | Gas Operator | Nov 2020 |
| 12 | Hinto Energy, LLC | Edwards, CO 81632 | Oil Operator | Mar 2017 |
| 13 | Hofland, James D. | Kevin, MT 59454 | Oil & Gas Operator | Sep 2025 |
| 14 | Home-Stake Oil & Gas Company | Plano, TX 75093 | Oil & Gas Operator | Sep 2025 |
| 15 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 16 | HR Energy LLC | Shelby, MT 59474 | Oil & Gas Operator | Sep 2025 |
| 17 | HRC Operating, LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2017 |
| 18 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2002 |
| 19 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Nov 2025 |
| 20 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 21 | Humble Oil & Refining Co. | Houston, TX 77252 | Oil & Gas Operator | Jan 2000 |
| 22 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Nov 2025 |
| 23 | Huntington Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2006 |