| 201 | Us Ore Corporation | Pacific Beach, CA 92109 | Oil Operator | Feb 2014 |
| 202 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2024 |
| 203 | USA Energy LLC | Lance Creek, WY 82222 | Oil & Gas Operator | Nov 2023 |
| 204 | USA Exploration & Production LLC | Mills, WY 82644 | Oil & Gas Operator | Sep 2012 |
| 205 | USA Superior Energy LLC | Houston, TX 77077 | Oil Operator | Mar 2010 |
| 206 | USA Tubulars, Inc. | Valley Spring, TX 76885 | Oil & Gas Operator | Dec 1995 |
| 207 | Uscan Oil Inc | Oil City, PA 16301-1412 | Oil & Gas Operator | Dec 1991 |
| 208 | Usedc Okc LLC | | Oil & Gas Operator | May 2018 |
| 209 | Usfg Oil & Gas, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Dec 2005 |
| 210 | Usins Oil Compan | | Oil Operator | Jan 1993 |
| 211 | Usx Operating Co., Inc. | Barnstall, OK 74002 | Oil & Gas Operator | Apr 2017 |
| 212 | Utah Gas Op LTD | Rangely, CO 81648 | Oil & Gas Operator | Feb 2024 |
| 213 | Utah Oil LLC | Rantoul, KS 66079 | Oil Operator | Dec 2023 |
| 214 | Utah-Westar DRL Ventures | Dallas, TX 75201 | Oil & Gas Operator | Nov 1987 |
| 215 | Ute Energy Upstream Holdings LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2012 |
| 216 | Utex Oil Company | Elko, NV 89803 | Oil & Gas Operator | Dec 1988 |
| 217 | Utica Resource Operating LLC | Marietta, OH 45750 | Oil & Gas Operator | Sep 2023 |
| 218 | Utility Ventures Company | Pasadena, TX 77504 | Oil & Gas Operator | Apr 2024 |
| 219 | Utoco, LTD. | Midland, TX 79704 | Oil Operator | Apr 2024 |
| 220 | Uvalde Energy Co. | Austin, TX 78747 | Oil & Gas Operator | Nov 1994 |