| 29701 | Union Crude Operating Co. | Baytown, TX 77521 | Oil Operator | Aug 2003 |
| 29702 | Union Development Company Inc | | Oil & Gas Operator | Dec 1992 |
| 29703 | Union Diversified, Inc. | | Gas Operator | Dec 2008 |
| 29704 | Union Drilling &Management Inc | | Gas Operator | Feb 1991 |
| 29705 | Union Expl. Partners, LTD. | | Oil & Gas Operator | Aug 1990 |
| 29706 | Union Gas Operating Company | Spring, TX 77391 | Oil & Gas Operator | May 2026 |
| 29707 | Union Oil Co | Danville, OH 43014 | Oil & Gas Operator | Dec 2014 |
| 29708 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 29709 | Union Operating Corp | Lakewoord, CO 80215 | Oil Operator | Dec 2023 |
| 29710 | Union Pacific Austin Chalk Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 29711 | Union Pacific Re | | Oil & Gas Operator | Dec 1996 |
| 29712 | Union Pacific Resour | | Oil & Gas Operator | Apr 2002 |
| 29713 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 29714 | Union Petro Inc | Uniontown, KY 42461 | Oil Operator | Dec 2024 |
| 29715 | Union Petrochemical | | Oil & Gas Operator | Dec 1982 |
| 29716 | Union Producing Co. | | Gas Operator | Dec 1992 |
| 29717 | Union Royalty, Inc. | Midland, TX 79706 | Oil & Gas Operator | Jul 2014 |
| 29718 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 29719 | Union Springs Central School District | Union Springs, NY 13160 | Gas Operator | Dec 2024 |
| 29720 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 29721 | Union Texas Petroleum Corp | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 29722 | Union Valley Petroleum Corp | Enid, OK 73701 | Oil & Gas Operator | Mar 2026 |
| 29723 | Unionville Explo | | Oil Operator | Jul 1984 |
| 29724 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Feb 2026 |
| 29725 | Unit Manager, Citronelle Unit | | Oil & Gas Operator | Sep 2001 |
| 29726 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2026 |
| 29727 | United Company | Lubbock, TX 79408 | Oil & Gas Operator | Jun 1995 |
| 29728 | United Energy & Expl Inc | Ada, OK 74821-2449 | Oil & Gas Operator | Mar 2026 |
| 29729 | United Energy & Exploration LLC | Ada, OK 74821 | Oil & Gas Operator | Mar 2026 |
| 29730 | United Energy Corporation | San Antonio, TX 78209 | Oil & Gas Operator | May 2026 |
| 29731 | United Energy Develop Co LTD | Bartlesville, OK 74003 | Oil Operator | Mar 2004 |
| 29732 | United Energy Operating, LLC | Edmond, OK 73083 | Oil & Gas Operator | May 2026 |
| 29733 | United Energy Partners, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 29734 | United Energy, Inc. | Wichita, KS 67230 | Oil & Gas Operator | Dec 2002 |
| 29735 | United Gas Pipe Line Co. | | Oil Operator | Aug 1993 |
| 29736 | United Investment Group | | Oil Operator | Nov 2004 |
| 29737 | United Meridian | | Oil Operator | Dec 1992 |
| 29738 | United Natural Gas LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2020 |
| 29739 | United Natural Resources Corp | | Oil Operator | Jan 1986 |
| 29740 | United O&G/Atlee Miller | Millersburg, OH 44654 | Oil & Gas Operator | Dec 1985 |
| 29741 | United Oil & Gas | | Oil Operator | Feb 1988 |
| 29742 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 29743 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 29744 | United Oil & Shale LLC | Woodward, OK 73801 | Oil & Gas Operator | May 2026 |
| 29745 | United Oil Corporation | Denver, CO 80202-3813 | Oil & Gas Operator | Feb 2026 |
| 29746 | United Operating Company | Olney, TX 76374 | Oil & Gas Operator | Aug 2003 |
| 29747 | United Operating, LLC *** | Midland, TX 79710 | Oil & Gas Operator | May 2026 |
| 29748 | United Operators, Inc. | | Oil Operator | Sep 1999 |
| 29749 | United Petro LTD. | | Oil & Gas Operator | Dec 2018 |
| 29750 | United Petroleum | | Oil Operator | Mar 1986 |
| 29751 | United Petroleum & Gas, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2026 |
| 29752 | United Petroleum Corporation | Edgwater, CO 80214 | Oil & Gas Operator | May 1996 |
| 29753 | United Petroleum Technologies | Hondo, TX 78861 | Oil & Gas Operator | Aug 2001 |
| 29754 | United Primary Resources Inc | Milton, WA 98354-9361 | Oil & Gas Operator | Feb 2016 |
| 29755 | United Producers Inc | Broken Arrow, OK 74012-8247 | Oil & Gas Operator | Mar 2020 |
| 29756 | United Producing Co Inc | | Oil & Gas Operator | May 1961 |
| 29757 | United Production Company LLC | Edmond, OK 73003 | Oil & Gas Operator | Mar 2026 |
| 29758 | United Reserve G | | Oil Operator | Aug 1987 |
| 29759 | United Resources Corp | Olean, NY 14760 | Oil & Gas Operator | Dec 2020 |
| 29760 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 29761 | United Resources LP A Texas LMTD PRNTSHP | Austin, TX 78746 | Oil & Gas Operator | Sep 2003 |
| 29762 | United Security Associates Inc | | Oil & Gas Operator | Dec 2020 |
| 29763 | United Southern Resources Inc. | | Gas Operator | Nov 2013 |
| 29764 | United States Exploration, Inc. | Denver, CO 80802 | Oil & Gas Operator | Apr 2007 |
| 29765 | United States Gypsum Company | Oakfield, NY 14125 | Oil & Gas Operator | Dec 2024 |
| 29766 | United Texas Oil LLC | Houston, TX 77027 | Oil & Gas Operator | May 2026 |
| 29767 | United Texas Petroleum Inc. | McKinney, TX 75070 | Oil & Gas Operator | May 2026 |
| 29768 | United Utilities Corporation | Conroe, TX 77301 | Oil & Gas Operator | Oct 1998 |
| 29769 | United Well Completion, Inc | Corbin, KY 40701 | Oil & Gas Operator | Dec 2024 |
| 29770 | United World Energy Corporation | | Oil & Gas Operator | Dec 2024 |
| 29771 | United World Energy, Inc. | Aurora, CO 80040 | Oil & Gas Operator | May 2026 |
| 29772 | Unitex Oil & Gas, L.L.C. | Midland, TX 79701 | Oil & Gas Operator | May 2026 |
| 29773 | Unity Petroleum | Howard, OH 43028 | Oil & Gas Operator | Dec 2021 |
| 29774 | Universal Cyclops Specialty Steel Div | Pittsburgh, PA 15228-2702 | Gas Operator | Dec 1985 |
| 29775 | Universal Drilling Company | Denver, CO 80203 | Oil & Gas Operator | Sep 2003 |
| 29776 | Universal Exploration Inc | Wadsworth, OH 44281-9460 | Oil & Gas Operator | Feb 2012 |
| 29777 | Universal Fuels Company | | Oil & Gas Operator | Oct 1993 |
| 29778 | Universal Geopower LLC | Houston, TX 77057 | Oil & Gas Operator | May 2016 |
| 29779 | Universal Land | | Oil Operator | Dec 2024 |
| 29780 | Universal Oil Co. | | Oil Operator | Jan 2025 |
| 29781 | Universal Operating, Inc | Evansville, IN 47715 | Oil & Gas Operator | Dec 2024 |
| 29782 | Universal Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2002 |
| 29783 | Universal Producers, Inc. | | Oil Operator | Jun 2001 |
| 29784 | Universal Resour | | Oil & Gas Operator | Dec 1996 |
| 29785 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 29786 | Universal Resources Holdings Inc | Dunkirk, NY 14048 | Oil & Gas Operator | Dec 2024 |
| 29787 | University Field Management LLC | | Oil Operator | Nov 2024 |
| 29788 | Unknown | Houston, TX 77208 | Oil & Gas Operator | Dec 2024 |
| 29789 | Unknown Owner | Columbus, OH 43229 | Oil & Gas Operator | Dec 2008 |
| 29790 | Unocal Explor. Corp. | | Oil & Gas Operator | Nov 1990 |
| 29791 | Unocal Exploration Corporation | Houston, TX 77001 | Oil & Gas Operator | May 1992 |
| 29792 | Unoco, Inc. | Kerrville, TX 78029 | Oil & Gas Operator | Jan 1999 |
| 29793 | Unoso Operating Company L.L.C. | Georgetown, TX 78633 | Oil & Gas Operator | May 2026 |
| 29794 | Unrein Oil Co | | Oil Operator | Jan 2026 |
| 29795 | Unruh, Elmer | Galva, KS 67443 | Oil & Gas Operator | Aug 1998 |
| 29796 | Unruh, Mark D. | Peru, KS 67360 | Oil Operator | Sep 2011 |
| 29797 | Unswept Oil Company | Corsicana, TX 75151 | Oil & Gas Operator | Jan 2018 |
| 29798 | Untamed Resources, LLC | Spearman, TX 79081 | Gas Operator | May 2026 |
| 29799 | Untener Bishop Kenneth (Diocese Of Saginaw) | | Oil Operator | Dec 2025 |
| 29800 | Uosi Operating, Inc. | Lovelady, TX 75851 | Oil & Gas Operator | May 2026 |