| 801 | Mineral Resources & Engineering | Aladdin, WY 82710 | Oil Operator | Jul 1991 |
| 802 | Mingo Oil Producers | Salt Lake City, UT 84111 | Oil & Gas Operator | Nov 1987 |
| 803 | Minnelusa Oil LLC | Temecula, CA 92589 | Oil Operator | Feb 2002 |
| 804 | Misahar Investments | Evergreen, CO 80439 | Oil Operator | Dec 1992 |
| 805 | Mitchell Energy Corp | Houston, TX 77002 | Oil & Gas Operator | Aug 2013 |
| 806 | Mitchell M J | | Oil & Gas Operator | Jan 1983 |
| 807 | MKM Services Inc | | Oil Operator | Aug 2026 |
| 808 | Mobil Expl & Producing North America Inc | | Oil & Gas Operator | Nov 1986 |
| 809 | Moco Oil Inc | | Oil Operator | May 1984 |
| 810 | Mon-Oil Inc | | Oil & Gas Operator | Apr 1996 |
| 811 | Monahan Rex | Sterling, CO 80751 | Oil & Gas Operator | Jun 2002 |
| 812 | Moncrief W A Jr | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2026 |
| 813 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 814 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 815 | Montex Drilling Company LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2026 |
| 816 | Montex Exploration | Sugarland, TX 77478 | Oil Operator | Apr 2003 |
| 817 | Monument Global Resources Inc | Dallas, TX 75243 | Oil & Gas Operator | Jan 2025 |
| 818 | Morgan Energy Corporation | Englewood, CO 80110 | Oil & Gas Operator | Mar 2006 |
| 819 | Morning Star Oil Company | Thermopolis, WY 82443 | Oil Operator | Feb 2025 |
| 820 | Morsey Oil & Gas Corporation | Corpus Christ, TX 78401 | Oil & Gas Operator | Sep 2026 |
| 821 | Mosbacher Production Co. | Houston, TX 77001 | Oil & Gas Operator | Aug 1984 |
| 822 | Moss Properties Inc | | Oil & Gas Operator | Mar 1986 |
| 823 | Mountain Hawk Energy LLC | Athens, TX 75751 | Gas Operator | Jan 2015 |
| 824 | Mountain Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Apr 2013 |
| 825 | Mountain Resource Corporation | Salt Lake City, UT 84124 | Oil & Gas Operator | Dec 1988 |
| 826 | MRD Operating LLC (Delaware) | Houston, TX 77010 | Oil & Gas Operator | Jul 2015 |
| 827 | MTG Operating Inc | Ridgeland, MS 39158 | Gas Operator | Apr 2011 |
| 828 | Mueller Fred W | | Oil & Gas Operator | Dec 1995 |
| 829 | Mull Drilling Company | Wichita, KS 67206 | Oil & Gas Operator | May 2026 |
| 830 | Mundell F E | Watertown, SD 57201 | Oil & Gas Operator | Aug 1994 |
| 831 | Murex Petroleum Corporation | Humble, TX 77347 | Oil & Gas Operator | Jun 2026 |
| 832 | Murphy D V | | Oil Operator | Dec 1989 |
| 833 | Murphy Oil USA, Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 834 | Murphy Sheldon L & Loretta | Newcastle, WY 82701 | Oil & Gas Operator | Jul 2026 |
| 835 | Mustang Oil & Gas Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Jul 2021 |
| 836 | Mustang Resources LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2026 |
| 837 | MWJ Producing Company | Midland, TX 79701 | Oil & Gas Operator | Jul 1998 |
| 838 | Mystique Developments | Denver, CO 80202 | Oil & Gas Operator | Dec 1997 |
| 839 | Nadel And Gussman Rockies, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2012 |
| 840 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 841 | Nanke Energy LLC | Westminster, CO 80234 | Oil & Gas Operator | Jul 2026 |
| 842 | National Energy Group Inc | Dallas, TX 75206 | Oil & Gas Operator | Sep 2014 |
| 843 | National Fuel Corporation | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Jul 2026 |
| 844 | National Oil Company | Garden City, KS 67846 | Oil & Gas Operator | Jun 2024 |
| 845 | National Pride Operating | Parker, CO 80134 | Oil & Gas Operator | Dec 2017 |
| 846 | National Treasure Mines | San Marina, CA 91118 | Oil Operator | Dec 1998 |
| 847 | Natomas North America Inc | | Oil & Gas Operator | Aug 1993 |
| 848 | Natrona County Holdings LLC | Austin, TX 78701 | Oil & Gas Operator | Nov 2020 |
| 849 | Natural Gas Corp Of California | Vernal, UT 84078 | Oil & Gas Operator | Dec 1989 |
| 850 | Natural Gas Processing Company | Worland, WY 82401 | Oil & Gas Operator | Jul 2026 |
| 851 | Natural Resource Corporation | Rock Springs, WY 82901 | Oil & Gas Operator | Sep 1983 |
| 852 | Nautilus Exploration LLC | Denver, CO 80218 | Oil Operator | Mar 2011 |
| 853 | Navigation Powder River LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2026 |
| 854 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | Sep 2026 |
| 855 | Nella Company LTD | | Oil Operator | Dec 1986 |
| 856 | Nepeco | Byron, WY 82412 | Oil Operator | Jun 2026 |
| 857 | New Era Oil/Preferred Energy | | Oil & Gas Operator | Sep 1993 |
| 858 | New Era Petroleum Inc | Sheridan, WY 82801 | Oil Operator | Jul 2026 |
| 859 | New Horizon Resources LLC | Houston, TX 77057 | Oil & Gas Operator | Sep 2026 |
| 860 | Neward Corporation | FT. Worth, TX 76102 | Oil & Gas Operator | Dec 1997 |
| 861 | Newcastle Oil & Gas Inc | | Oil Operator | Dec 1988 |
| 862 | Newfield Production Company | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2021 |
| 863 | Newman Bros Drilling | | Oil & Gas Operator | Apr 2004 |
| 864 | Newport Gas Partners LLC | Gillette, WY 82716 | Oil & Gas Operator | Oct 2025 |
| 865 | Newport Oil Corporation | Clearwater, FL 33755 | Oil & Gas Operator | Jul 2011 |
| 866 | Newton Steve Drilling | Worland, WY 82401 | Oil Operator | Apr 2001 |
| 867 | Newwoods Petroleum LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2016 |
| 868 | Nextraction Energy Us Inc | Las Vegas, NV 89169 | Oil & Gas Operator | Feb 2018 |
| 869 | Nicolaysen G G Jr | | Oil & Gas Operator | Dec 1995 |
| 870 | Nicor Exploration | | Oil Operator | Jul 1993 |
| 871 | Nicor Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Jun 1993 |
| 872 | Nielson & Associates, Inc | Cody, WY 82414 | Oil & Gas Operator | Feb 2016 |
| 873 | Nielson Capital Partners LLC | Cody, WY 82414 | Oil & Gas Operator | Dec 2014 |
| 874 | Noarko Resources | | Oil & Gas Operator | Mar 1990 |
| 875 | Noble Energy Inc | Midland, TX 79706 | Oil & Gas Operator | Sep 2026 |
| 876 | Nonsuch Natural Gas Inc | Naples, FL 34108 | Oil & Gas Operator | Jul 2026 |
| 877 | Nor-Am Exploration | | Oil Operator | Jun 1981 |
| 878 | Norcen Energy Inc | | Oil Operator | Dec 1989 |
| 879 | Nordstrand Engineering Inc | Houston, TX 77019 | Oil & Gas Operator | Sep 2026 |
| 880 | Nortex Gas & Oil Co | Tulsa, OK 74135 | Oil & Gas Operator | Sep 1993 |
| 881 | North Central Oil Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2005 |
| 882 | North Finn LLC | Casper, WY 82605 | Oil & Gas Operator | Jul 2026 |
| 883 | North Shore Exploration & Prod LLC | Broomfield, CO 80021 | Oil & Gas Operator | Jul 2026 |
| 884 | North Silo Resources LLC | Houston, TX 77055 | Oil & Gas Operator | Jul 2026 |
| 885 | Northern Michigan Expl Co | | Oil & Gas Operator | Jul 1990 |
| 886 | Northern Production Co | Gillette, WY 82717 | Oil & Gas Operator | Apr 2013 |
| 887 | Northern Pump Company | Denver, CO 80202-3130 | Oil & Gas Operator | Feb 2006 |
| 888 | Northstar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Jun 2024 |
| 889 | Northstar Operating Company Of Texas | Midland, TX 79702 | Oil & Gas Operator | Feb 2008 |
| 890 | Northwest Energy LLC | Buffalo, WY 82834 | Gas Operator | Jan 2010 |
| 891 | Northwest Exploration | | Oil & Gas Operator | Dec 1984 |
| 892 | Northwoods Land Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 893 | Norton Frickey | Lakewood, CO 80215 | Oil & Gas Operator | Dec 2023 |
| 894 | Nova Energy Inc | Casper, WY 82601 | Oil & Gas Operator | Oct 2020 |
| 895 | Nova Petroleum Cororation | | Oil & Gas Operator | Mar 1987 |
| 896 | Nucor Oil & Gas Inc | Riverton, WY 82501 | Oil & Gas Operator | Jun 2026 |
| 897 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Sep 2026 |
| 898 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 899 | Oci LLC | Thermopolis, WY 82443 | Oil Operator | Jan 2024 |
| 900 | Oedekoven Amerifields Resources LLC | Sugar Land, TX 77478 | Oil Operator | Jun 2026 |