| 501 | Cougar Oil | | Oil Operator | Feb 2025 |
| 502 | Coughlin, Daniel L | | Oil Operator | Aug 2000 |
| 503 | Council Oak Resources LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | May 2025 |
| 504 | County Line Stripper Wells LLC | Chelsea, OK 74016 | Oil & Gas Operator | May 2025 |
| 505 | Countyline Production Co LLC | Duncan, OK 73533 | Oil Operator | Jun 2025 |
| 506 | Couroil, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Sep 2000 |
| 507 | Courson Oil & Gas, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Oct 2025 |
| 508 | Courson, Harold D. | Perryton, TX 79070 | Oil & Gas Operator | Aug 1998 |
| 509 | Cousins Exploration Co | Wichita Falls, TX 76307 | Oil Operator | Jun 1991 |
| 510 | Cove Petroleum Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2020 |
| 511 | Covenant Oil Corp | Broken Arrow, OK 74014 | Oil & Gas Operator | May 2013 |
| 512 | Covington Oil Company Inc | Nichols Hills, OK 73116 | Oil & Gas Operator | Jun 2025 |
| 513 | Cow Creek Resources Inc | Ponca City, OK 74601-7815 | Oil & Gas Operator | Jul 2025 |
| 514 | Cowboy Oil & Gas | Bristow, OK 74010-0057 | Oil & Gas Operator | Jul 2018 |
| 515 | Cowboy Operating LLC | Oklahoma City, OK 73120 | Oil Operator | Jun 2025 |
| 516 | Cowden SR Lester L | Oklahoma City, OK 73118-4011 | Oil & Gas Operator | Sep 1999 |
| 517 | Cowles James C | Muskogee, OK 74401-5262 | Oil Operator | Jan 2025 |
| 518 | Cox Edwin L & R Berry | Dallas, TX 75202 | Oil & Gas Operator | Apr 2015 |
| 519 | Cox Elmer N | Irving, TX 75181 | Oil Operator | Aug 2013 |
| 520 | Cox Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1999 |
| 521 | Cox Gas Corporation | Dallas, TX 75201-7306 | Oil & Gas Operator | Apr 2015 |
| 522 | Cox Linda | Bristow, OK 74010-0808 | Oil & Gas Operator | Jan 2018 |
| 523 | Cox Oil & Gas, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 524 | Cox P D Inc | Bristow, OK 74010 | Oil & Gas Operator | May 1993 |
| 525 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 526 | Cox Robert L | Blackwell, OK 74631 | Oil & Gas Operator | Mar 2025 |
| 527 | Cox, Gary L | | Oil Operator | Mar 2022 |
| 528 | Cox, John L. | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 529 | CPRC Inc | Tulsa, OK 74103-5037 | Oil & Gas Operator | Apr 1997 |
| 530 | CPRP Services LLC | Oklahoma City, OK 73102-5804 | Oil & Gas Operator | Jul 2025 |
| 531 | Crabtree Barbara T | Forney, TX 75126-5818 | Oil & Gas Operator | Oct 2024 |
| 532 | Craft & Craft Productions LLC | | Oil Operator | May 2025 |
| 533 | Craig Elder Oil And Gas LLC | Edmond, OK 73013 | Oil & Gas Operator | Jun 2025 |
| 534 | Crain & Deisenroth | Tulsa, OK 74103-4433 | Oil & Gas Operator | Mar 2015 |
| 535 | Crain & Deisenroth LLC | Tulsa, OK 74104-6511 | Oil & Gas Operator | Apr 2014 |
| 536 | Crain Minerals LLC | Oklahoma City, OK 73120-1004 | Oil & Gas Operator | Aug 2014 |
| 537 | Cramer Oil LLC | Nowata, OK 74048-6011 | Oil Operator | Jun 2025 |
| 538 | Crasco Oil Company | Tulsa, OK 74120 | Oil Operator | Nov 1998 |
| 539 | Craw Operating LLC | Mooreland, OK 73852 | Oil & Gas Operator | Jun 2025 |
| 540 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 541 | CRB Resources Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Jun 2025 |
| 542 | CRD Investments LLC | Duncan, OK 73533-4226 | Oil Operator | Jun 2025 |
| 543 | Creede Oil & Gas Company | Oklahoma City, OK 73102-7502 | Oil & Gas Operator | Jun 2006 |
| 544 | Creek Ellis | Haskell, OK 74436 | Oil & Gas Operator | Mar 2012 |
| 545 | Crescendo Resources, L.P. | Amarillo, TX 79188 | Oil & Gas Operator | Jun 2025 |
| 546 | Crescent Exploration, LLC | Edmond, OK 73013 | Oil & Gas Operator | Mar 2015 |
| 547 | Creslenn Oil Company | | Oil & Gas Operator | Nov 1998 |
| 548 | Crest Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2025 |
| 549 | Crew B Operating, LLC | Okmulgee, OK 74447 | Oil Operator | Jun 2025 |
| 550 | Cricket Enterprises Corporation | Nowata, OK 74048-9683 | Oil & Gas Operator | Mar 2015 |
| 551 | Criswell Energy LLC | Montezuma, IA 50171-8500 | Oil & Gas Operator | Oct 2022 |
| 552 | CRM Energy Partners | | Oil & Gas Operator | Jun 2025 |
| 553 | Cromer Carroll Oil & Gas LLC | Kalispell, MT 59901 | Oil & Gas Operator | Jun 2025 |
| 554 | Crooch John | Okmulgee, OK 74447 | Oil Operator | May 2025 |
| 555 | Cross Don | Cushing, OK 74023-6316 | Oil & Gas Operator | Feb 2022 |
| 556 | Cross Timbers Oil Company | Dallas, TX 75284 | Oil & Gas Operator | May 2013 |
| 557 | Cross Timbers Operating Co | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2025 |
| 558 | Cross Timbers Production Co | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 2005 |
| 559 | Cross, Don E | | Oil & Gas Operator | Jan 2013 |
| 560 | Crouch Petroleum Company | Amarillo, TX 79110 | Oil & Gas Operator | Mar 2015 |
| 561 | Crow Creek Operating Co III LLC | Tulsa, OK 74137-8432 | Oil & Gas Operator | Apr 2015 |
| 562 | Crow Oil LLC | Tulsa, OK 74133-2914 | Oil & Gas Operator | Sep 2019 |
| 563 | Crown Central Pet Corp | Bellaire, TX 77401 | Oil & Gas Operator | Dec 2016 |
| 564 | Crown Consulting, Inc. | Liberal, KS 67905 | Oil & Gas Operator | Jun 2025 |
| 565 | Crown Energy Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Jun 2025 |
| 566 | Crown Petroleum Company | Duncan, OK 73534-0938 | Oil & Gas Operator | Jan 2011 |
| 567 | Crude Oil Recovery Inc /Osage Only | | Oil & Gas Operator | Mar 2006 |
| 568 | Crude Resources | Sapulpa, OK 74066 | Oil & Gas Operator | Mar 2008 |
| 569 | Crumpton H A | Duncan, OK 73533 | Oil Operator | Dec 2002 |
| 570 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 571 | Crusader Energy Group Inc. | Austin, TX 78746 | Oil & Gas Operator | Mar 2015 |
| 572 | Crusader Energy Group LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2015 |
| 573 | Crusader Energy II LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 574 | Crusader Energy III LLC | Oklahoma City, OK 73142-1856 | Oil & Gas Operator | Feb 2011 |
| 575 | Crusher Oil Company | Ponca City, OK 74604-5612 | Oil Operator | Apr 2017 |
| 576 | Cruzen Drilling Company Inc | Cleveland, OK 74020-0470 | Oil Operator | Nov 2014 |
| 577 | Crystal Energy Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Feb 2019 |
| 578 | Csoda Operating Company LLC | Amarillo, TX 79114-7506 | Oil & Gas Operator | Aug 2021 |
| 579 | CSX Oil & Gas Corporation | Houston, TX 77210-4326 | Oil & Gas Operator | Mar 1993 |
| 580 | Cudd Operating Corp. | Oklahoma City, OK 73118 | Oil & Gas Operator | Apr 2020 |
| 581 | Cuesta Petroleum Inc | Shawnee, OK 74801-6963 | Oil & Gas Operator | Jun 2025 |
| 582 | Culbreath Oil & Gas Company, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Jun 2025 |
| 583 | Culebra Oil & Gas LLC | Kerrville, TX 78028 | Oil & Gas Operator | Oct 2025 |
| 584 | Culp & Copple Oil Company | Cushing, OK 74023 | Oil & Gas Operator | Jun 2025 |
| 585 | Cumberland Operating Company | Seminole, OK 74868-1258 | Oil & Gas Operator | Mar 2007 |
| 586 | Cummings Gene | | Oil Operator | Dec 2000 |
| 587 | Cummings Oil & Cattle | Ada, OK 74820-0994 | Oil Operator | Jan 2017 |
| 588 | Cummings Oil Company | Oklahoma City, OK 73112-6113 | Oil & Gas Operator | Jul 2025 |
| 589 | Cummins Wren Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Nov 1998 |
| 590 | Cundiff Harold | Perkins, OK 74059-4199 | Oil & Gas Operator | Apr 2025 |
| 591 | Cundiff Jack | Perkins, OK 74059-4198 | Oil & Gas Operator | Apr 2014 |
| 592 | Curn Lisa | Steubenville, OH 43952-2535 | Oil Operator | Jun 2025 |
| 593 | Curran Oil Co | Great Falls, MT 59401 | Gas Operator | May 2001 |
| 594 | Curzon Operating Company LTD | Oklahoma City, OK 73118-4821 | Oil & Gas Operator | Jun 2025 |
| 595 | CVR Supply & Trading, LLC | Sugar Land, TX 77479 | Oil & Gas Operator | Apr 2024 |
| 596 | CW Investments | Okmulgee, OK 74447-4026 | Oil & Gas Operator | Jun 2025 |
| 597 | CWB Energy Inc | Oklahoma City, OK 73139-8837 | Oil Operator | May 2000 |
| 598 | CX Disposals LLC | Minco, OK 73059-9472 | Oil Operator | Jul 2025 |
| 599 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 600 | Cyanostar Energy, Inc | Tulsa, OK 74103-4122 | Oil & Gas Operator | Sep 2001 |