| 901 | McConnell Oil Properties | | Oil Operator | Mar 2025 |
| 902 | McCool John E | Youngsville, PA 16371 | Oil & Gas Operator | May 2025 |
| 903 | McCord Al Inc | Norman, OK 73072-6720 | Oil & Gas Operator | Feb 2011 |
| 904 | McCord Exploration Co. | | Oil & Gas Operator | Dec 1990 |
| 905 | McCord J K | Duncan, OK 73534-0032 | Oil Operator | Mar 2009 |
| 906 | McCord Oil Co. And T. Walker | | Oil & Gas Operator | Dec 1985 |
| 907 | McCord-Dale Exploration | | Oil & Gas Operator | May 1986 |
| 908 | McCord-Goodrich Oil Company | | Oil & Gas Operator | Oct 1991 |
| 909 | McCorgary Martin E | Arkansas City, KS 67005-5452 | Oil & Gas Operator | Feb 2025 |
| 910 | McCorgary Operations | | Oil & Gas Operator | Jan 2025 |
| 911 | McCorkle, Frank R. & Kathleen A. | Sedan, KS 67361 | Oil Operator | Oct 2009 |
| 912 | McCormack, Lowell Ray | Gainesville, TX 76240 | Oil & Gas Operator | Dec 1993 |
| 913 | McCormack, Paul H. | Gainesville, TX 76241 | Oil & Gas Operator | Sep 2003 |
| 914 | McCormick Operating Company | | Oil & Gas Operator | Mar 1984 |
| 915 | McCormick Operating PRTNSHP | | Oil & Gas Operator | Sep 1985 |
| 916 | McCormick Operating, L.L.C. | Olney, TX 76374 | Oil Operator | Sep 2015 |
| 917 | McCormick Production Co, Inc. | Oil City, LA 71061 | Oil & Gas Operator | Jul 2025 |
| 918 | McCormick, Mark | Java Center, NY 14082 | Gas Operator | Dec 2024 |
| 919 | McCormick, Ronald R. | Java Center, NY 14082 | Gas Operator | Dec 2024 |
| 920 | McCormick, Terrance & Anne | Andover, NY 14806 | Oil & Gas Operator | Dec 2024 |
| 921 | McCormick-Bintliff | | Oil & Gas Operator | Feb 1984 |
| 922 | McCormick-Bintliff-Pettit | | Oil & Gas Operator | Feb 1984 |
| 923 | McCormick-Ciroco, Inc. | | Oil & Gas Operator | Jan 1984 |
| 924 | McCormick-Terra-Bintliff | | Oil & Gas Operator | Dec 1979 |
| 925 | McCormick-WHB | | Gas Operator | Jan 1984 |
| 926 | McCort Brian L | Malaga, OH 43757 | Oil & Gas Operator | Dec 2024 |
| 927 | McCown Engineering | Wichita Falls, TX 76310 | Oil & Gas Operator | Jul 2025 |
| 928 | McCoy Alex W & Associates | Tulsa, OK 74170 | Oil & Gas Operator | Mar 2009 |
| 929 | McCoy Natural Gas Co | Oil City, PA 16301-3003 | Gas Operator | Dec 1995 |
| 930 | McCoy Petroleum | | Oil & Gas Operator | Aug 1996 |
| 931 | McCoy Petroleum Corporation | Wichita, KS 67207 | Oil & Gas Operator | Jun 2025 |
| 932 | McCoy Production | El Dorado, KS 67042 | Oil Operator | Dec 2019 |
| 933 | McCoy, Jon | Erie, KS 66733 | Oil Operator | Jan 2025 |
| 934 | McCracken Energy Services, LLC | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 935 | McCracken Oil & Gas, LLC | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 936 | McCracken, Carl A. III | | Oil & Gas Operator | Dec 2012 |
| 937 | McCracken, Cory | Bradford, PA 16701 | Oil & Gas Operator | Dec 2024 |
| 938 | McCracken, H. L. Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2025 |
| 939 | McCrary & Franklin, Inc. | Post, TX 79356 | Oil & Gas Operator | May 2012 |
| 940 | McCrary Oil Company, Inc. | College Sta, TX 77840 | Oil & Gas Operator | Sep 2019 |
| 941 | McCraw Family Limited Partnership (The) | Konawa, OK 74849-5616 | Oil & Gas Operator | Jul 2024 |
| 942 | McCrea Exploration Company, Inc. | Carrollton, TX 75007 | Oil & Gas Operator | Nov 1995 |
| 943 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Apr 2025 |
| 944 | McCulliss Resource Company Inc | Denver, CO 80202 | Oil & Gas Operator | Jun 1999 |
| 945 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 946 | McCulloch Geothermal Corporation | | Oil & Gas Operator | Jun 1982 |
| 947 | McCulloch Oil Corp Of Ca | | Oil & Gas Operator | May 1980 |
| 948 | McCulloch Oil Corp.-Ids | | Oil & Gas Operator | Dec 1981 |
| 949 | McCullough G W | Norman, OK 73072 | Oil & Gas Operator | Aug 2000 |
| 950 | McCullough, Richard F. | Pennsboro, WV 26415 | Oil & Gas Operator | Dec 2021 |
| 951 | McCurdy Energy LLC | Midland, TX 79705 | Oil Operator | Jul 2025 |
| 952 | McCurdy Oil Co. | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2025 |
| 953 | McCutchin Alma Estate | Dallas, TX 75380 | Oil & Gas Operator | May 2013 |
| 954 | McCutchin Petroleum Corporation | Dallas, TX 75225 | Oil & Gas Operator | Jul 2025 |
| 955 | McCutchin, Gene | Dallas, TX 75380 | Oil & Gas Operator | Aug 2003 |
| 956 | McCutchin, Jerry | Dallas, TX 75380 | Oil & Gas Operator | Mar 2008 |
| 957 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | Jul 2025 |
| 958 | McDaniel Oil Co. | Marble Falls, TX 78654 | Oil & Gas Operator | Jul 2025 |
| 959 | McDaniel Petroleum Company, Inc. | | Oil Operator | Jun 2020 |
| 960 | McDaniel, Willard | Iraan, TX 79744 | Oil & Gas Operator | Nov 2004 |
| 961 | McDaniel, Willard Jr. Oil Co. | Marble Falls, TX 78654 | Oil & Gas Operator | Mar 2005 |
| 962 | McDay Energy Corp. | Dallas, TX 75206 | Oil & Gas Operator | Jul 2025 |
| 963 | McDe Energy Company Inc | Enid, OK 73706 | Oil & Gas Operator | May 2009 |
| 964 | McDonald & Johnson Resources,LLC | Cypress, TX 77429 | Oil & Gas Operator | Dec 2010 |
| 965 | McDonald & Pomeroy Operating Co. | Pasadena, TX 77506 | Oil & Gas Operator | Aug 2003 |
| 966 | McDonald Dale E | Frazeysburg, OH 43822 | Oil & Gas Operator | Dec 2024 |
| 967 | McDonald Energy, Inc. | Granbury, TX 76049 | Oil & Gas Operator | Jul 2025 |
| 968 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 969 | McDonald Production, LLC | Lubbock, TX 79408 | Oil Operator | Jul 2025 |
| 970 | McDonald Ranch Partnership | | Oil Operator | Apr 2025 |
| 971 | McDonald Resources, LLC | Jefferson, TX 75657 | Oil & Gas Operator | Jul 2025 |
| 972 | McDonald, Joe | Burkburnett, TX 76354 | Oil & Gas Operator | Aug 1995 |
| 973 | McDonald, R. A. Oil Co. | Borger, TX 79008 | Oil & Gas Operator | Oct 2002 |
| 974 | McDonald, Richard A. | Fredericksbrg, TX 78624 | Oil & Gas Operator | Jul 2025 |
| 975 | McDonnold Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 976 | McDowell And Cook, Inc. | | Oil Operator | Jan 1987 |
| 977 | McDowell Ranch | Shamrock, TX 79079 | Gas Operator | Jul 2025 |
| 978 | McElroy Drilling Co., Inc. | | Gas Operator | Dec 1987 |
| 979 | McElroy John | Sapulpa, OK 74066-6119 | Oil & Gas Operator | Apr 2025 |
| 980 | McElvain Energy Inc | Denver, CO 80265 | Oil & Gas Operator | Nov 2019 |
| 981 | McElvain Oil & Gas Properties Inc | Denver, CO 80265-2080 | Oil & Gas Operator | Jul 2011 |
| 982 | McEn 1996 Partnership | | Oil & Gas Operator | Sep 1999 |
| 983 | McEna Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jul 2005 |
| 984 | McEuen, Billy Oil Co. | Bowie, TX 76230 | Oil & Gas Operator | Dec 2016 |
| 985 | McEver Oil Company Inc. | Austin, TX 78789 | Oil & Gas Operator | Mar 2008 |
| 986 | MCF Co. | | Oil & Gas Operator | Dec 2011 |
| 987 | McFadden Energy TX, LLC | Lakewood, NY 14750 | Oil Operator | Jul 2025 |
| 988 | McFadden Oil Co. | | Oil Operator | Mar 2025 |
| 989 | McFarland & Scobey, Inc. | El Paso, TX 79947 | Oil & Gas Operator | Jul 2025 |
| 990 | McFarland Energy, Inc. | New Orleans, LA 70160 | Oil & Gas Operator | Dec 2009 |
| 991 | McFerran Operating LLC | Seminole, OK 74868-6202 | Oil & Gas Operator | Apr 2025 |
| 992 | MCG Oil & Gas Operating, LLC | Archer City, TX 76351 | Oil & Gas Operator | Sep 2023 |
| 993 | McGee Drilling Corporation | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 994 | McGee, Tom Corporation | Booker, TX 79005 | Oil & Gas Operator | Apr 2025 |
| 995 | McGehee, George T. Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Oct 1997 |
| 996 | McGhee Exploration And Prod. Co. | Houston, TX 77019 | Oil & Gas Operator | Feb 2003 |
| 997 | McGinley Jr, John R | | Gas Operator | Nov 1998 |
| 998 | McGinley P A | Tulsa, OK 74101 | Oil & Gas Operator | Dec 1996 |
| 999 | McGinness Energy Company Inc | Wichita, KS 67206 | Oil & Gas Operator | Apr 2025 |
| 1000 | McGinness Oil Co | Wichita, KS 67202 | Oil & Gas Operator | Dec 2019 |