| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 2 | H D Oil Company | Thermopolis, WY 82443 | Oil Operator | Aug 2025 |
| 3 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 4 | Hallwood Petroleum | Denver, CO 80237 | Oil & Gas Operator | Dec 1997 |
| 5 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 6 | Hedges Spencer | Casper, WY 82604 | Oil Operator | Mar 2024 |
| 7 | Hot Springs Resources LTD | Casper, WY 82601 | Oil Operator | Dec 2014 |
| 8 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 9 | Husky Oil Company | Cody, WY 82414 | Oil & Gas Operator | Dec 1984 |