| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | Gary-Williams Production Company | Denver, CO 80202 | Oil & Gas Operator | May 2000 |
| 2 | Goldmark Engineering Inc | Casper, WY 82602 | Oil & Gas Operator | Oct 2004 |
| 3 | Granite Creek Energy LLC | Cody, WY 82414 | Oil & Gas Operator | Oct 2025 |
| 4 | Great Northern Gas Company | Denver, CO 80293-0602 | Oil & Gas Operator | Jun 2016 |
| 5 | Great Western Drilling Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2025 |
| 6 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |