| 301 | Landmark Oil & G | | Oil Operator | Nov 1987 |
| 302 | Landmark Oil Exp | | Oil Operator | Sep 1994 |
| 303 | Landmark Operating Company | Welty, OK 74833-3923 | Oil Operator | Aug 2015 |
| 304 | Landmark Production Company | MC Gregor, TX 76657 | Oil & Gas Operator | Oct 2010 |
| 305 | Landmark Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Feb 2025 |
| 306 | Landmark Venture Group No. 1, Inc. | | Oil & Gas Operator | Jan 2025 |
| 307 | Landmark Venture Group, Inc. | | Oil Operator | Dec 2008 |
| 308 | Landmaster Partners, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jun 2025 |
| 309 | Landmen Of Texas | Hondo, TX 78861 | Oil Operator | Feb 2007 |
| 310 | Landmen Of Texas, Inc. | Hondo, TX 78861 | Oil Operator | Dec 2016 |
| 311 | Landor Oil Co. | San Marcos, TX 78666 | Oil Operator | Jun 2025 |
| 312 | Landowner | Honolulu, HI | Oil & Gas Operator | Dec 2008 |
| 313 | Landprovest Inc | Cambridge, OH 43725-858-858 | Oil & Gas Operator | Dec 1993 |
| 314 | Landreth, Robert E. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 315 | Landrick O & G Operating, LLC | Midland, TX 79705 | Oil & Gas Operator | Jun 2025 |
| 316 | Landrum Petroleum Co., Inc. | Burkburnett, TX 76354 | Oil Operator | Mar 2008 |
| 317 | Landrum West, Inc. | Burkburnett, TX 76354 | Oil & Gas Operator | Dec 1997 |
| 318 | Landrum, W. A. | Byers, TX 76357 | Oil & Gas Operator | Apr 2002 |
| 319 | Lane Oil Company, LLC | Northern Cambria, PA 15714 | Oil Operator | Dec 2023 |
| 320 | Lane Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Jun 2025 |
| 321 | Lane, Lloyd L. | Buffalo, TX 75831 | Oil Operator | Jun 2025 |
| 322 | Laneer Resources Company | Abilene, TX 79608 | Oil & Gas Operator | Jun 2025 |
| 323 | Lanexco, Inc. | Sealy, TX 77474 | Oil & Gas Operator | Jun 2025 |
| 324 | Lanford Drilling Co., Inc. | | Oil Operator | Jun 1996 |
| 325 | Lang Herman Oil | | Oil & Gas Operator | Dec 1996 |
| 326 | Lang Larry D | Beverly, OH 45715 | Oil & Gas Operator | Dec 2024 |
| 327 | Lang, Herman - Marital Trust | Garden City, KS 67846 | Oil & Gas Operator | Feb 2025 |
| 328 | Lang, Kenneth R. | Garden City, KS 67846 | Oil & Gas Operator | Feb 2025 |
| 329 | Langasco Energy Corp | Alliance, OH 44601 | Oil & Gas Operator | Dec 1987 |
| 330 | Langford & Brigham Operating LLC | Austin, TX 78730 | Oil & Gas Operator | Jun 2025 |
| 331 | Langford Production Company, LLC | Haskell, TX 79521 | Oil & Gas Operator | Jun 2025 |
| 332 | Langford, G. E. | Abilene, TX 79604 | Oil & Gas Operator | Jan 2002 |
| 333 | Langford, R. C. Operating Co. | Rule, TX 79547 | Oil & Gas Operator | Mar 1994 |
| 334 | Langham Petroleum Expl. Corp. | Houston, TX 77056 | Oil & Gas Operator | Dec 2009 |
| 335 | Langley Energy | Euless, TX 76040 | Gas Operator | Jan 2016 |
| 336 | Langley Harold | Graham, OK 73437 | Oil Operator | Jan 2025 |
| 337 | Langley, James Operating Company, Inc | Smackover, AR 71762 | Oil & Gas Operator | Dec 2024 |
| 338 | Langley, Jerry Oil Company LLC | Smackover, AR 71762 | Oil Operator | Jan 2025 |
| 339 | Langston Oil & Gas LLC | Wichita, KS 67202 | Oil Operator | Feb 2025 |
| 340 | Lankford & Nance | | Gas Operator | Dec 2010 |
| 341 | Lankford Oil Co. | Weatherford, TX 76086 | Oil & Gas Operator | Jul 1999 |
| 342 | Lankford, Dan L. | Graham, TX 76450 | Oil & Gas Operator | Jun 2025 |
| 343 | Lanmarc Resources | | Oil Operator | Dec 2003 |
| 344 | Lanoco, Inc. | | Oil & Gas Operator | Sep 2002 |
| 345 | Lansden Operating Co LLC | Norman, OK 73070 | Oil & Gas Operator | Dec 1997 |
| 346 | Lansing Energy C | | Oil Operator | Jun 2006 |
| 347 | Lansing Energy Operations | Wichita, KS 67202 | Oil Operator | Apr 2010 |
| 348 | Lapco Oil & Gas Company | Houston, TX 77069 | Oil & Gas Operator | Oct 2015 |
| 349 | Lapetco Inc | Plano, TX 75093 | Oil & Gas Operator | Aug 2024 |
| 350 | Lapis Operating, Inc. | Houston, TX 77042 | Oil & Gas Operator | Jul 2015 |
| 351 | Lappin Oil LLC | Douglas, WY 82633 | Oil & Gas Operator | May 2025 |
| 352 | Laquey, E. C. | Refugio, TX 78377 | Oil & Gas Operator | Aug 2003 |
| 353 | Lar-Mie Petroleum Inc | Tulsa, OK 74136 | Oil & Gas Operator | Aug 1998 |
| 354 | Larae Operations | Luling, TX 78648 | Oil Operator | Jun 2025 |
| 355 | Laramie Energy II LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2015 |
| 356 | Laramie Energy LLC | | Oil & Gas Operator | Aug 2013 |
| 357 | Laran Operating LLC | Dover, OK 73734-0057 | Oil & Gas Operator | Mar 2015 |
| 358 | Larance Engineering Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Jan 1996 |
| 359 | Larch Oil & Gas Corporation | Cross Lanes, WV 25313 | Oil & Gas Operator | Dec 2021 |
| 360 | Larco Drilling & Exploration Corp. | | Oil & Gas Operator | Dec 1999 |
| 361 | Larcom Mike | | Oil Operator | Feb 1987 |
| 362 | Lardo, Anthony P. Jr. | Lakeview, NY 14085 | Gas Operator | Dec 2023 |
| 363 | Laredo Energy | Houston, TX 77002 | Oil & Gas Operator | Jun 2016 |
| 364 | Laredo Energy Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | Nov 2022 |
| 365 | Laredo Energy, LP | Houston, TX 77040 | Oil & Gas Operator | Oct 2003 |
| 366 | Laredo Petroleum - Dallas, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Nov 2014 |
| 367 | Laredo Petroleum Inc | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2023 |
| 368 | Large Operating LLC | Stinnett, TX 79083 | Oil & Gas Operator | Jun 2025 |
| 369 | Large, William C. & Mary B. | Union Springs, NY 13160 | Gas Operator | Dec 2023 |
| 370 | Largo Oil Company | Longview, TX 75606 | Oil & Gas Operator | Jun 2025 |
| 371 | Lariat Energy & Supply Co Inc | Hulbert, OK 74441 | Oil & Gas Operator | Mar 2025 |
| 372 | Lariat Land & Exploration, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Jun 2025 |
| 373 | Lariat Petroleum Inc | Tulsa, OK 74119 | Oil & Gas Operator | Sep 2024 |
| 374 | Lariat Resources, LLC | Fort Worth, TX 76109 | Oil & Gas Operator | May 2022 |
| 375 | Lario Oil & Gas | | Oil & Gas Operator | Nov 1995 |
| 376 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | Jun 2025 |
| 377 | Larison Oil Company | Katy, TX 77494 | Oil & Gas Operator | Jun 2025 |
| 378 | Lark Production, Inc. | | Oil & Gas Operator | Mar 2023 |
| 379 | Larkin Energy Company Inc | Sasakwa, OK 74867 | Oil & Gas Operator | May 2022 |
| 380 | Larkin Oil Co | Sasakwa, OK 74867 | Oil & Gas Operator | Aug 2015 |
| 381 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Mar 2025 |
| 382 | Larmore Jr James E | Bartlesville, OK 74006-8312 | Oil Operator | Mar 2017 |
| 383 | Laroca Resources, LTD | Austin, TX 78709 | Oil & Gas Operator | Jun 2025 |
| 384 | Laroco LLP | Woodsboro, TX 78393 | Oil & Gas Operator | Mar 2008 |
| 385 | Laron Oil Corporation | Seguin, TX 78155 | Oil & Gas Operator | Jul 1997 |
| 386 | Larrette Resources | | Oil Operator | Nov 1999 |
| 387 | Larron Energy Corporation | New Braunfels, TX 78132 | Oil & Gas Operator | Mar 2015 |
| 388 | Larry A And Patricia D Jeter | Lovington, NM 88260 | Oil & Gas Operator | Apr 2000 |
| 389 | Larry Brown Dba Brown Oil Company | Ardmore, OK 73401 | Oil Operator | Apr 2015 |
| 390 | Larry E. Bedrosian | | Oil Operator | Dec 1999 |
| 391 | Larry H Wright Inc | Naples, FL 34108-2156-2156 | Oil & Gas Operator | Dec 1993 |
| 392 | Larry Marker Dba Marker Oil | Roswell, NM 88202 | Oil & Gas Operator | Jul 2017 |
| 393 | Larry Oil, Inc. | Albany, TX 76430 | Oil & Gas Operator | Nov 2001 |
| 394 | Larry Sherman Oil LLC | Chandler, OK 74834 | Oil & Gas Operator | Jan 2025 |
| 395 | Larry Wolff Dba Wolff'S Oilfield Service | Cushing, OK 74023-9789 | Oil & Gas Operator | Feb 2025 |
| 396 | Larson Buford | | Oil Operator | May 2006 |
| 397 | Larson Drilling Corp. | Jamestown, NY 14702 | Gas Operator | Dec 2023 |
| 398 | Larson Exploration Company | Tulsa, OK 74136-4939 | Oil & Gas Operator | Jul 2016 |
| 399 | Larson Operating | | Oil & Gas Operator | Mar 2001 |
| 400 | Larson Operating Company | Olmitz, KS 67564-8561 | Oil & Gas Operator | Dec 2019 |