| 1 | C & J Oil | | Oil & Gas Operator | Mar 2025 |
| 2 | C & M Oil Co. & Investments | | Oil & Gas Operator | Apr 2025 |
| 3 | C. C. Killingsworth Opr. | | Oil Operator | Dec 1999 |
| 4 | Caac 100 LLC | | Oil & Gas Operator | Mar 2025 |
| 5 | Caballero Operations LLC | | Oil & Gas Operator | Apr 2025 |
| 6 | Caleco LLC | | Oil & Gas Operator | Apr 2025 |
| 7 | California Petroleum Group Inc. | | Oil Operator | Mar 2025 |
| 8 | California Resources Elk Hills LLC | | Oil & Gas Operator | Apr 2025 |
| 9 | California Resources Production Corporation | | Oil & Gas Operator | Apr 2025 |
| 10 | Calresources LLC | | Oil & Gas Operator | Dec 1996 |
| 11 | Camtex Industries Inc. | | Oil Operator | Dec 1996 |
| 12 | Capco Resource Corporation | Orange,, CA 92869 | Oil Operator | Sep 2007 |
| 13 | Capital Production Company | | Oil Operator | Dec 1997 |
| 14 | Capitol Oil Corporation | | Oil & Gas Operator | Mar 2025 |
| 15 | Casex Company | | Oil & Gas Operator | Dec 2007 |
| 16 | Cather-Herley Oil Company | | Oil & Gas Operator | Apr 2025 |
| 17 | Celeron Oil & Gas Company | | Oil & Gas Operator | Dec 1987 |
| 18 | Cemco-Edison No. 1 (F.R.) Partnership | | Oil & Gas Operator | Dec 2000 |
| 19 | Central California Oil Co. | Fish Camp, CA 93623 | Oil & Gas Operator | Apr 2025 |
| 20 | Central Lease Inc. | | Oil & Gas Operator | Dec 1998 |
| 21 | Central Pacific Resources | | Oil Operator | Apr 2025 |
| 22 | Central Resources Inc | Denver, CO 80203 | Oil & Gas Operator | Dec 2019 |
| 23 | Century Exploration Resources LLC | | Oil & Gas Operator | Dec 2015 |
| 24 | CFT Oil & Gas LLC | | Oil Operator | Apr 2025 |
| 25 | Challenger Minerals Inc. | | Oil & Gas Operator | Dec 1991 |
| 26 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 27 | Channel Exploration Company | | Oil & Gas Operator | Feb 1997 |
| 28 | Chaparral Petroleum Inc. | | Oil Operator | Mar 2025 |
| 29 | Charles W. Hinesley | | Oil & Gas Operator | Dec 1991 |
| 30 | Chester F. Dolley | | Oil & Gas Operator | Dec 1986 |
| 31 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Jun 2025 |
| 32 | Citadel Exploration Inc. | | Oil Operator | Mar 2025 |
| 33 | Clearfield Energy Resources & Management Inc. | | Oil & Gas Operator | Dec 1998 |
| 34 | Cmo Inc. | | Oil Operator | Apr 2025 |
| 35 | Coffee Petroleum | | Oil & Gas Operator | Apr 2025 |
| 36 | Commander Oil Company LTD. | | Oil & Gas Operator | Dec 2021 |
| 37 | Compass Global Resources LLC | | Oil & Gas Operator | Dec 2015 |
| 38 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 39 | Core Energy LLC | | Oil & Gas Operator | Apr 2025 |
| 40 | Crimson Resource Management Corp. | | Oil & Gas Operator | Apr 2025 |
| 41 | Crupper Operating & Trading Company | | Oil & Gas Operator | Dec 1996 |