| 301 | Hays Herb E & K S | Bartlesville, OK 74006 | Oil Operator | Mar 2025 |
| 302 | Hays Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2000 |
| 303 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Apr 2025 |
| 304 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 305 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 306 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 307 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Mar 2025 |
| 308 | Helton Oil Company | Edmond, OK 73083-7283 | Oil & Gas Operator | Aug 2016 |
| 309 | Henry Petroleum Inc | Oklahoma City, OK 73162-1757 | Oil & Gas Operator | Sep 2019 |
| 310 | Heritage Oil Company | Norman, OK 73070 | Oil & Gas Operator | Jul 2008 |
| 311 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Jul 2025 |
| 312 | Herrmann Arnold | Chandler, OK 74834 | Oil & Gas Operator | Sep 2024 |
| 313 | Hiawatha Exploration Company | Oklahoma City, OK 73116-7326 | Oil & Gas Operator | Mar 2009 |
| 314 | High Energy | Cushing, OK 74023 | Oil & Gas Operator | Apr 2025 |
| 315 | Hightower Energy LLC | Cushing, OK 74023-6370 | Oil & Gas Operator | May 2025 |
| 316 | Hill Gilford | Stroud, OK 74079-9401 | Oil & Gas Operator | May 2013 |
| 317 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Apr 2025 |
| 318 | Hill Resources Inc | | Oil & Gas Operator | Nov 2022 |
| 319 | Hills Dozer Service | Stroud, OK 74079 | Oil & Gas Operator | Mar 2022 |
| 320 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Apr 2025 |
| 321 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 322 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | May 2025 |
| 323 | HLH Realty Co | Drumright, OK 74030 | Oil & Gas Operator | Mar 2016 |
| 324 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | May 2025 |
| 325 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 326 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 327 | Hoppes Helen E | Depew, OK 74028-3428 | Oil & Gas Operator | Apr 2015 |
| 328 | Horizon Resources Inc | Fort Worth, TX 76101-1978 | Oil & Gas Operator | Jul 2006 |
| 329 | Hovas Enterprises | Perkins, OK 74059 | Oil & Gas Operator | Mar 2014 |
| 330 | Howco Oil And Gas | Stroud, OK 74079-9604 | Oil & Gas Operator | Mar 2015 |
| 331 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 332 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 333 | Indrex Inc | Tulsa, OK 74133 | Oil & Gas Operator | Dec 2000 |
| 334 | Inland Oil Corporation | Sapulpa, OK 74066 | Oil & Gas Operator | Jan 2025 |
| 335 | International Energy Company LLC | Tulsa, OK 74136-3922 | Oil & Gas Operator | Apr 2025 |
| 336 | International Ventures, Inc. | Pogasa Springs, CO 81147 | Oil Operator | Jul 1996 |
| 337 | Investment Operating Co | Stillwater, OK 74075-8572 | Oil Operator | May 2025 |
| 338 | J O C Operating Inc | Fort Worth, TX 76102-6823 | Oil & Gas Operator | Feb 2021 |
| 339 | J O MC Oil & Gas Inc | Maud, OK 74854 | Oil & Gas Operator | Apr 1999 |
| 340 | Jac-Mac Energy Corporation | Oklahoma City, OK 73170 | Oil & Gas Operator | May 2025 |
| 341 | James Larry | Guthrie, OK 73044-9622 | Oil & Gas Operator | Apr 2025 |
| 342 | James Lawrence E Estate Of | Crescent, OK 73028-9304 | Oil & Gas Operator | Nov 2021 |
| 343 | Jan Oil Company | Oklahoma City, OK 73156 | Oil & Gas Operator | May 2006 |
| 344 | Jay Petroleum Inc | Oklahoma City, OK 73154-0526 | Oil & Gas Operator | Mar 2019 |
| 345 | JB Production Company | Denton, TX 76202 | Oil & Gas Operator | Jul 2004 |
| 346 | JCN Petroleum Corporation | Edmond, OK 73083-3357 | Oil & Gas Operator | Jun 2004 |
| 347 | Jec Operating LLC | Oklahoma City, OK 73114-2717 | Oil & Gas Operator | Apr 2025 |
| 348 | Jefferson Co LLC (The) | Corinth, TX 76205 | Oil & Gas Operator | Aug 2004 |
| 349 | Jeffries Pumping Service Inc | Guthrie, OK 73044-8761 | Oil & Gas Operator | Apr 2025 |
| 350 | Jenkins Petroleum Inc | Stillwater, OK 74076 | Oil & Gas Operator | Mar 1994 |
| 351 | Jet Oil Co12/Ofb See 18649 | | Oil & Gas Operator | Jul 2007 |
| 352 | Jimgas Inc | Magnolia, TX 77355 | Oil & Gas Operator | May 2016 |
| 353 | John Warden Inc | Wellston, OK 74881-8827 | Oil & Gas Operator | Nov 2014 |
| 354 | Johnson Doyle T | Oklahoma City, OK 73118-1007 | Oil & Gas Operator | Jan 2013 |
| 355 | Johnson Exploration Company | Oklahoma City, OK 73102-7008 | Oil & Gas Operator | Jun 2015 |
| 356 | Jones & Pellow Oil Co | Oklahoma City, OK 73118-1115 | Oil & Gas Operator | Feb 2015 |
| 357 | Jones Tank Trucks Inc | Cushing, OK 74023-8947 | Oil & Gas Operator | Dec 2000 |
| 358 | Jrhop Inc | Norman, OK 73072-4615 | Oil & Gas Operator | Dec 2015 |
| 359 | Juno Operating Company II LLC | Plano, TX 75093 | Oil & Gas Operator | Sep 2018 |
| 360 | K & H Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Dec 1995 |
| 361 | K & L Operating LLC | Cushing, OK 74023 | Oil & Gas Operator | May 2025 |
| 362 | K Energy Inc | Mannford, OK 74044-3023 | Oil & Gas Operator | May 2013 |
| 363 | K S Oil Company Inc | Norman, OK 73072-7480 | Oil & Gas Operator | May 2025 |
| 364 | Kahan And Associates, Inc | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2025 |
| 365 | Kaiser Investments | Sand Springs, OK 74063 | Oil & Gas Operator | Sep 2003 |
| 366 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 367 | Kate F H | Oklahoma City, OK 73122 | Oil & Gas Operator | Jun 2000 |
| 368 | Kato Operating Company | Bristow, OK 74010 | Oil & Gas Operator | Mar 2015 |
| 369 | Keener Oil Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2018 |
| 370 | Kelco Petroleum Inc | Oklahoma City, OK 73120 | Oil & Gas Operator | May 2013 |
| 371 | Kemp Roy L | | Oil Operator | Jan 2011 |
| 372 | Keno Oil & Gas Inc | Hennessey, OK 73742 | Oil & Gas Operator | Jan 1995 |
| 373 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 374 | Kerr-McGee Refining Corp | Oklahoma City, OK 73125 | Oil & Gas Operator | Jun 2007 |
| 375 | Kibtec Oil & Gas Inc | Cashion, OK 73016 | Oil & Gas Operator | Aug 2024 |
| 376 | Kingery Drilling Co., Inc. | Ardmore, OK 73402 | Oil & Gas Operator | May 2025 |
| 377 | Kingfisher CSG Pullr & Const Inc | Hennessey, OK 73742-0024 | Oil & Gas Operator | Apr 2014 |
| 378 | KN Production Co. | Lakewood, CO 80228 | Oil & Gas Operator | Jun 2003 |
| 379 | Koby Oil Company LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2025 |
| 380 | Koch Oil Company | | Oil & Gas Operator | May 2017 |
| 381 | Kolar Petroleum Inc | Oklahoma City, OK 73162-1509 | Oil & Gas Operator | Jun 2007 |
| 382 | Kolibri Energy Us, Inc. | Thousand Oaks, CA 91320-1272 | Oil & Gas Operator | Apr 2025 |
| 383 | KWB Oil Property Management Inc | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2025 |
| 384 | L & N Exploration Inc | | Oil & Gas Operator | Jul 2013 |
| 385 | Ladder Energy Company | Tulsa, OK 74120-4281 | Oil & Gas Operator | Jan 2018 |
| 386 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Apr 2025 |
| 387 | Lance Ruffel Oil & Gas LLC | Oklahoma City, OK 73102-5632 | Oil & Gas Operator | May 2025 |
| 388 | Landers & Musgrove | Okemah, OK 74859 | Oil & Gas Operator | Mar 2015 |
| 389 | Landers & Musgrove Oil Co. Inc | Okemah, OK 74859-0266 | Oil & Gas Operator | Jan 2018 |
| 390 | Landers & Waldman Inc | Okemah, OK 74859-0660 | Oil & Gas Operator | May 2013 |
| 391 | Landers Oil & Gas Inc | Tulsa, OK 74132-2171 | Oil & Gas Operator | Apr 2025 |
| 392 | Lar-Mie Petroleum Inc | Tulsa, OK 74136 | Oil & Gas Operator | Aug 1998 |
| 393 | Larkspur Operating LLC | Oklahoma City, OK 73034 | Oil & Gas Operator | Apr 2025 |
| 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 | May 2025 |
| 396 | Las Colinas Oil Corp. | Irving, TX 75062 | Oil & Gas Operator | Mar 2015 |
| 397 | Laurel Operating Company, Inc. | Stillwater, OK 74074-3025 | Oil & Gas Operator | Apr 2025 |
| 398 | Le Norman Energy Corporation | Duncan, OK 73534 | Oil & Gas Operator | Nov 2014 |
| 399 | Leasehold Management Corp | Oklahoma City, OK 73107 | Oil & Gas Operator | Nov 2024 |
| 400 | Leavell Resources Corporation | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |