| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | Chorney Oil Co | Denver, CO 80203 | Oil & Gas Operator | Mar 1975 |
| 2 | Cities Serv Oil & Gas Corp | Oklahoma City, OK 73112 | Oil & Gas Operator | Sep 1964 |
| 3 | Coastal Plains Energy Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 2026 |
| 4 | Cockrell Oil Corporation | Houston, TX 77002-7348 | Oil & Gas Operator | Feb 2001 |
| 5 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 6 | Cordillera Corporation | Denver, CO 80237 | Oil & Gas Operator | Feb 1996 |