| 6001 | Clifford & Scott McKeever | Clarksburg, PA 15725 | Gas Operator | Dec 2024 |
| 6002 | Clifford C. Or Mary A. Terry | Dadeville, AL 36853 | Oil Operator | Feb 2003 |
| 6003 | Clifford Resourc | | Oil & Gas Operator | Mar 1989 |
| 6004 | Clifford Resources Inc | Oklahoma City, OK 73120 | Oil & Gas Operator | Jul 2015 |
| 6005 | Cliffs Drilling Company | | Oil & Gas Operator | Dec 1984 |
| 6006 | Cliffs Oil And Gas Company | | Oil & Gas Operator | Oct 1997 |
| 6007 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 6008 | Clift Cary E | Chickasha, OK 73018-6305 | Oil & Gas Operator | Jun 2025 |
| 6009 | Clifton & Associates Inc | Tulsa, OK 74133 | Oil & Gas Operator | May 2020 |
| 6010 | Clifton Consulting Inc | Piedmont, OK 73078-0180 | Gas Operator | Sep 2025 |
| 6011 | Clifton Oil | Muenster, TX 76252 | Oil & Gas Operator | Mar 2006 |
| 6012 | Clifton, B.W. | Graham, TX 76450 | Oil & Gas Operator | Mar 2000 |
| 6013 | Clifton, Joe B. Exploration, Inc | Pauls Valley, OK 73075 | Oil & Gas Operator | Mar 2008 |
| 6014 | Climax Oil Co LLC | Comanche, OK 73529-7715 | Oil Operator | Aug 2025 |
| 6015 | Clinch Drilling Company | | Oil & Gas Operator | Jan 2000 |
| 6016 | Clindco Inc | Bartlesville, OK 74006-6213 | Oil & Gas Operator | Oct 2019 |
| 6017 | Cline Oil Inc | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 6018 | Cline Production Company | Billings, MT 59104 | Oil & Gas Operator | Oct 2025 |
| 6019 | Clint H. Woodington | | Oil Operator | Dec 1994 |
| 6020 | Clinton Bowers Estate | Manhatten, KS 66502 | Oil Operator | Dec 1998 |
| 6021 | Clinton Gas Marketing Inc | Columbus, OH 43214 | Oil & Gas Operator | Dec 1988 |
| 6022 | Clinton Oil Company | Wichita, KS 67202 | Oil & Gas Operator | Apr 1980 |
| 6023 | Clinton Petroleum Co Inc | Randolph, OH 44265 | Oil & Gas Operator | Dec 2009 |
| 6024 | Clinton Producti | | Oil Operator | Dec 1989 |
| 6025 | Clinton Production, Inc. | Wichita, KS 67206 | Oil & Gas Operator | Jun 2025 |
| 6026 | Clinton Public Works Authority | Clinton, OK 73601 | Oil & Gas Operator | May 2023 |
| 6027 | Clinton, Orville L., Jr. | Paola, KS 66071 | Oil Operator | Apr 2005 |
| 6028 | Clipper Operating Co., Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jan 2000 |
| 6029 | CLK Energy Partners, LLC | | Oil & Gas Operator | Aug 2018 |
| 6030 | CLM Oil Production Inc | Bartlesville, OK 74006-4417 | Oil & Gas Operator | Oct 2025 |
| 6031 | CLM Operating | Graham, TX 76450 | Oil & Gas Operator | Aug 2017 |
| 6032 | Cloer VIrgil R | Oklahoma City, OK 73121 | Oil & Gas Operator | Apr 1993 |
| 6033 | Clofas Case Oil Co. | | Oil & Gas Operator | Sep 2025 |
| 6034 | Close, Bryan H. | Shamrock, TX 79079 | Gas Operator | Dec 2025 |
| 6035 | Clothier, David W. | Eastborough, KS 67206 | Oil & Gas Operator | Dec 2019 |
| 6036 | Cloud Peak Operating LLC | Casper, WY 82601 | Oil Operator | Oct 2025 |
| 6037 | Clovelly DRLG & Dev Co Inc | | Oil & Gas Operator | Oct 1983 |
| 6038 | Clovelly Oil Co. LLC | | Oil & Gas Operator | Nov 2024 |
| 6039 | Clovelly Oil Co., Inc. | | Oil & Gas Operator | Nov 2008 |
| 6040 | Clovelly Oil Co., Inc. - Ripco | | Oil & Gas Operator | Nov 1991 |
| 6041 | Clover Energy Corp | | Oil & Gas Operator | May 1980 |
| 6042 | Clover Oil Company | | Oil Operator | May 2025 |
| 6043 | Clover Production Company | Sourlake, TX 77659 | Oil & Gas Operator | Dec 2025 |
| 6044 | Clowser Well Service, Inc. | | Oil & Gas Operator | Dec 2021 |
| 6045 | CLR Gauging Corp. | Tuleta, TX 78162 | Oil & Gas Operator | Dec 2025 |
| 6046 | CLR Secondary Recovery, LLC | Wichita Falls, TX 76306 | Oil & Gas Operator | Dec 2025 |
| 6047 | CLS Interests, Incorporated | Austin, TX 78734 | Oil & Gas Operator | Jan 1997 |
| 6048 | CLS Petroleum Holdings LLC | Iowa Park, TX 76367 | Oil Operator | Dec 2025 |
| 6049 | Clsog L.C. | Houston, TX 77024 | Gas Operator | Jun 2008 |
| 6050 | Clubine, Jim L. | Independence, KS 67301 | Oil Operator | Nov 2024 |
| 6051 | Clute Oil Corporation | Cherry Hills VIllage, CO 80113 | Oil & Gas Operator | Jun 2025 |
| 6052 | CLV Oil & Gas Inc | Tulsa, OK 74169-0713 | Oil & Gas Operator | Apr 2020 |
| 6053 | Clyde B. Baker Opr. | | Gas Operator | Dec 1995 |
| 6054 | Clyde G. Kissinger | | Oil Operator | Jun 1964 |
| 6055 | Clyde H & Rae M Peters | Waterford, PA 16441-8872 | Gas Operator | Dec 2007 |
| 6056 | Clyde Petroleum | | Oil & Gas Operator | Dec 1988 |
| 6057 | Clyde W. Jones | | Oil Operator | Sep 2003 |
| 6058 | Clydesdale Energy LLC | Oklahoma City, OK 73116-9111 | Oil & Gas Operator | Nov 2019 |
| 6059 | Clymar, Inc | New Lexington, OH 43764 | Oil & Gas Operator | Dec 1996 |
| 6060 | CM Exploration Company Inc. | | Oil & Gas Operator | Apr 2009 |
| 6061 | CM Oil Co. | FT Stockton, TX 79735 | Oil & Gas Operator | Dec 2025 |
| 6062 | CM Oil Co., L.L.C. | | Oil Operator | Jan 2025 |
| 6063 | CM Production, LLC | | Oil & Gas Operator | Aug 2020 |
| 6064 | CM TX Production, LLC | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2023 |
| 6065 | CM5 Resources, LLC | Artesia, NM 88211 | Oil & Gas Operator | Sep 2025 |
| 6066 | Cmint Productions LLC | Dallas, TX 75248-2643 | Oil Operator | Oct 2021 |
| 6067 | CML Exploration, LLC | Austin, TX 78746 | Oil & Gas Operator | Dec 2025 |
| 6068 | Cmo Inc. | | Oil Operator | Sep 2025 |
| 6069 | Cmo LLC | Cleveland, OK 74020 | Oil & Gas Operator | Aug 2025 |
| 6070 | CMR Energy, L.P. | Houston, TX 77077 | Oil & Gas Operator | Dec 2025 |
| 6071 | CMR Oil, LLC | McKinney, TX 75072 | Oil Operator | Dec 2025 |
| 6072 | CMR Operating LLC | Tulsa, OK 74135-2653 | Oil & Gas Operator | Jun 2018 |
| 6073 | CMS Energy Inc | Dallas, TX 75287 | Oil & Gas Operator | Oct 2025 |
| 6074 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 6075 | CMS Oil And Gas Company | Jackson, MI 49201 | Oil & Gas Operator | Oct 2002 |
| 6076 | CMT Oil & Gas Company Inc | Tulsa, OK 74133-6724 | Oil & Gas Operator | Sep 2025 |
| 6077 | CMT Operating LLC | Cleveland, OK 74020-0113 | Oil & Gas Operator | Mar 2015 |
| 6078 | CMW Oil Company | | Oil & Gas Operator | Dec 1976 |
| 6079 | CMX Inc Of Kansas | Wichita, KS 67206-2561 | Oil & Gas Operator | Oct 2025 |
| 6080 | CMX, Inc. | Wichita, KS 67206 | Oil & Gas Operator | Jun 2025 |
| 6081 | CNC Oil Co., Inc. | | Oil Operator | Aug 1991 |
| 6082 | CNG Development Co | | Oil & Gas Operator | Dec 2008 |
| 6083 | CNG Producing | New Orleans, LA 70112-6000 | Oil & Gas Operator | Jun 2000 |
| 6084 | CNG Producing Co.-Tulsa Div. | | Oil & Gas Operator | Jun 1986 |
| 6085 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 6086 | CNR Resources Inc | Houston, TX 77002-4103 | Oil & Gas Operator | May 2005 |
| 6087 | CNS Energy, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Nov 2010 |
| 6088 | CNX Gas Company LLC | Canonsburg, PA 15317 | Oil & Gas Operator | Sep 2025 |
| 6089 | Co Energy | Benbrook, TX 76126 | Oil & Gas Operator | Dec 2025 |
| 6090 | Co-Co Incorporat | | Oil Operator | Oct 1989 |
| 6091 | Co-Co Oil, Inc. | Lubbock, TX 79407 | Oil & Gas Operator | Aug 2003 |
| 6092 | Co-St Oil Operating Co Inc | Enid, OK 73706 | Oil & Gas Operator | Apr 1997 |
| 6093 | Co-Wil-Co, Incorporated | | Oil Operator | Dec 1990 |
| 6094 | Coachman Energy Operating Co, LLC | Englewood, CO 80111 | Oil Operator | May 2024 |
| 6095 | Coal Creek Energy, LLC | Overland Park, KS 66221 | Oil Operator | Dec 2019 |
| 6096 | Coal Creek Minerals LLC | Northglenn, CO 80234 | Gas Operator | Feb 2012 |
| 6097 | Coal Gas Recovery II LLC | Waynesburg, PA 15370 | Gas Operator | Dec 2017 |
| 6098 | Coal Gas Recovery LLC | Waynesburg, PA 15370-2330 | Gas Operator | Dec 2012 |
| 6099 | Coal Gas Recovery LP | Linthicum Heights, MD 21090-2227 | Gas Operator | Dec 2010 |
| 6100 | Coal Gas Transportation LLC | Cadiz, OH 43907 | Gas Operator | Dec 2016 |