| 1 | C & R Drilling C | | Oil Operator | Aug 1994 |
| 2 | C & S Oil Company, LLC | Russell, KS 67665 | Oil Operator | Jun 2025 |
| 3 | C C & S Oil Oper | | Oil Operator | Apr 1983 |
| 4 | C G Oil, Inc. | Victoria, KS 67671 | Oil Operator | Jun 2025 |
| 5 | C K Oil Company | Great Bend, KS 67530 | Oil & Gas Operator | Jun 2025 |
| 6 | Caerus Kansas LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 7 | Canaday Oil Corp | Goddard, KS 67052 | Oil & Gas Operator | Jun 2025 |
| 8 | Carmen Schmitt, Inc. | Great Bend, KS 67530 | Oil & Gas Operator | Jun 2025 |
| 9 | Castelli Exploration, Inc. | Oklahoma City, OK 73162 | Oil & Gas Operator | Jun 2025 |
| 10 | Castle Resources, Inc. | Russell, KS 67665 | Oil & Gas Operator | Jun 2025 |
| 11 | Cattlemans Oil O | | Oil Operator | Nov 1995 |
| 12 | Cattlemans Oil Operations | | Oil Operator | Dec 2009 |
| 13 | Cattlemans Oil Operations LLC | Hays, KS 67601 | Oil Operator | Dec 2019 |
| 14 | Central Operating Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2025 |
| 15 | Challenger Exploration | | Oil Operator | Nov 2014 |
| 16 | Champion Petrole | | Oil Operator | Jan 1992 |
| 17 | Charter Energy, Inc. | Great Bend, KS 67530 | Oil Operator | Jun 2025 |
| 18 | Chesney Marilyn | | Oil Operator | Jul 1987 |
| 19 | Chevron U S A In | | Oil & Gas Operator | Sep 2000 |
| 20 | Chief Drilling C | | Oil & Gas Operator | Feb 1995 |
| 21 | Cholla Production LLC | Littleton, CO 80127 | Oil & Gas Operator | Jun 2025 |
| 22 | Christa Oil Comp | | Oil Operator | Nov 1994 |
| 23 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Oct 2025 |
| 24 | Cla-Mar Oil Company, LLC | Hays, KS 67601 | Oil Operator | Dec 2019 |
| 25 | Clair Oil, Inc. | Russell, KS 67665 | Oil Operator | Nov 2019 |
| 26 | Clinton Producti | | Oil Operator | Dec 1989 |
| 27 | Coastal Oil & Ga | | Oil & Gas Operator | Oct 1996 |
| 28 | Cobalt Energy LLC | Wichita, KS 67202 | Oil & Gas Operator | Jun 2025 |
| 29 | Cokan Resources | Colby, KS 67701 | Oil Operator | Aug 1994 |
| 30 | Col-Kan Developm | | Oil & Gas Operator | Jan 1995 |
| 31 | Collins John B | | Oil Operator | Sep 1994 |
| 32 | Colorado Crude E | | Oil Operator | Jan 1986 |
| 33 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 34 | Columbian Servic | | Oil & Gas Operator | Nov 1993 |
| 35 | Condor Energy | | Oil Operator | Aug 1995 |
| 36 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 37 | Continental Ener | | Oil & Gas Operator | Dec 1996 |
| 38 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 39 | Coral Production Corporation | Denver, CO 80201 | Oil & Gas Operator | Jun 2025 |
| 40 | Corie Oil Compan | | Oil Operator | Jul 1985 |
| 41 | Crazy Horse Oil | | Oil Operator | May 2025 |
| 42 | Curt'S Oil Operation, LLC | Hoisington, KS 67544 | Oil & Gas Operator | Jun 2025 |
| 43 | CWB Oil Company, LLC | St. Francis, KS 67756 | Oil Operator | Jun 2025 |