| 501 | Cotton County Ventures | Estes Park, CO 80517 | Oil Operator | Nov 2003 |
| 502 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 503 | Cottonmouth SWD LLC | Tulsa, OK 74103-3522 | Oil Operator | Dec 2025 |
| 504 | Couch Donald W | Marlow, OK 73055 | Oil & Gas Operator | Dec 2025 |
| 505 | Couch Fred J | Broken Arrow, OK 74012 | Oil Operator | Mar 2010 |
| 506 | Cougar Energy Investment LLC | Spring, TX 77387-7277 | Oil & Gas Operator | Sep 2014 |
| 507 | Cougar Oil | | Oil Operator | Jul 2025 |
| 508 | Coughlin, Daniel L | | Oil Operator | Aug 2000 |
| 509 | Council Oak Resources LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Dec 2025 |
| 510 | County Line Stripper Wells LLC | Chelsea, OK 74016 | Oil & Gas Operator | Dec 2025 |
| 511 | Countyline Production Co LLC | Duncan, OK 73533 | Oil Operator | Dec 2025 |
| 512 | Couroil, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Sep 2000 |
| 513 | Courson Oil & Gas, Inc. | Perryton, TX 79070 | Oil & Gas Operator | Mar 2026 |
| 514 | Courson, Harold D. | Perryton, TX 79070 | Oil & Gas Operator | Aug 1998 |
| 515 | Cousins Exploration Co | Wichita Falls, TX 76307 | Oil Operator | Jun 1991 |
| 516 | Cove Petroleum Corporation | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2020 |
| 517 | Covenant Oil Corp | Broken Arrow, OK 74014 | Oil & Gas Operator | May 2013 |
| 518 | Covington Oil Company Inc | Nichols Hills, OK 73116 | Oil & Gas Operator | Jan 2026 |
| 519 | Cow Creek Resources Inc | Ponca City, OK 74601-7815 | Oil & Gas Operator | Dec 2025 |
| 520 | Cowboy Oil & Gas | Bristow, OK 74010-0057 | Oil & Gas Operator | Jul 2018 |
| 521 | Cowboy Operating LLC | Oklahoma City, OK 73120 | Oil Operator | Dec 2025 |
| 522 | Cowden SR Lester L | Oklahoma City, OK 73118-4011 | Oil & Gas Operator | Sep 1999 |
| 523 | Cowles James C | Muskogee, OK 74401-5262 | Oil Operator | Sep 2025 |
| 524 | Cox Edwin L & R Berry | Dallas, TX 75202 | Oil & Gas Operator | Apr 2015 |
| 525 | Cox Elmer N | Irving, TX 75181 | Oil Operator | Aug 2013 |
| 526 | Cox Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1999 |
| 527 | Cox Gas Corporation | Dallas, TX 75201-7306 | Oil & Gas Operator | Apr 2015 |
| 528 | Cox Linda | Bristow, OK 74010-0808 | Oil & Gas Operator | Jan 2018 |
| 529 | Cox Oil & Gas Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 530 | Cox P D Inc | Bristow, OK 74010 | Oil & Gas Operator | May 1993 |
| 531 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 532 | Cox Robert L | Blackwell, OK 74631 | Oil & Gas Operator | Oct 2025 |
| 533 | Cox, Gary L | | Oil Operator | Mar 2022 |
| 534 | Cox, John L. | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 535 | CP Energy, LLC | Edmond, OK 73034 | Oil Operator | Jul 2025 |
| 536 | CPRC Inc | Tulsa, OK 74103-5037 | Oil & Gas Operator | Apr 1997 |
| 537 | CPRP Services LLC | Oklahoma City, OK 73102-5804 | Oil & Gas Operator | Dec 2025 |
| 538 | Crabtree Barbara T | Forney, TX 75126-5818 | Oil & Gas Operator | Oct 2024 |
| 539 | Craft & Craft Productions LLC | | Oil Operator | May 2025 |
| 540 | Craig Elder Oil And Gas LLC | Edmond, OK 73013 | Oil & Gas Operator | Dec 2025 |
| 541 | Crain & Deisenroth | Tulsa, OK 74103-4433 | Oil & Gas Operator | Mar 2015 |
| 542 | Crain & Deisenroth LLC | Tulsa, OK 74104-6511 | Oil & Gas Operator | Apr 2014 |
| 543 | Crain Minerals LLC | Oklahoma City, OK 73120-1004 | Oil & Gas Operator | Aug 2014 |
| 544 | Cramer Oil LLC | Nowata, OK 74048-6011 | Oil Operator | Dec 2025 |
| 545 | Crasco Oil Company | Tulsa, OK 74120 | Oil Operator | Nov 1998 |
| 546 | Craw Operating LLC | Mooreland, OK 73852 | Oil & Gas Operator | Dec 2025 |
| 547 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2026 |
| 548 | CRB Resources Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 2025 |
| 549 | CRD Investments LLC | Duncan, OK 73533-4226 | Oil Operator | Dec 2025 |
| 550 | Creede Oil & Gas Company | Oklahoma City, OK 73102-7502 | Oil & Gas Operator | Jun 2006 |
| 551 | Creek Ellis | Haskell, OK 74436 | Oil & Gas Operator | Mar 2012 |
| 552 | Crescendo Resources, L.P. | Amarillo, TX 79188 | Oil & Gas Operator | Dec 2025 |
| 553 | Crescent Exploration, LLC | Edmond, OK 73013 | Oil & Gas Operator | Mar 2015 |
| 554 | Creslenn Oil Co | | Oil & Gas Operator | Nov 1998 |
| 555 | Crest Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2026 |
| 556 | Crew B Operating, LLC | Okmulgee, OK 74447 | Oil Operator | Dec 2025 |
| 557 | Cricket Enterprises Corporation | Nowata, OK 74048-9683 | Oil & Gas Operator | Mar 2015 |
| 558 | Criswell Energy LLC | Montezuma, IA 50171-8500 | Oil & Gas Operator | Oct 2022 |
| 559 | CRM Energy Partners | | Oil & Gas Operator | Dec 2025 |
| 560 | Cromer Carroll Oil & Gas LLC | Kalispell, MT 59901 | Oil & Gas Operator | Nov 2025 |
| 561 | Crooch John | Okmulgee, OK 74447 | Oil Operator | Dec 2025 |
| 562 | Cross Don | Cushing, OK 74023-6316 | Oil & Gas Operator | Dec 2025 |
| 563 | Cross Timbers Oil Company | Dallas, TX 75284 | Oil & Gas Operator | May 2013 |
| 564 | Cross Timbers Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2025 |
| 565 | Cross Timbers Production Co | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 2005 |
| 566 | Cross, Don E | | Oil & Gas Operator | Jan 2013 |
| 567 | Crouch Petroleum Company | Amarillo, TX 79110 | Oil & Gas Operator | Mar 2015 |
| 568 | Crow Creek Operating Co III LLC | Tulsa, OK 74137-8432 | Oil & Gas Operator | Apr 2015 |
| 569 | Crow Oil LLC | Tulsa, OK 74133-2914 | Oil & Gas Operator | Sep 2019 |
| 570 | Crown Central Pet Corp | Bellaire, TX 77401 | Oil & Gas Operator | Dec 2016 |
| 571 | Crown Consulting Inc | Liberal, KS 67905 | Oil & Gas Operator | Sep 2025 |
| 572 | Crown Energy Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Dec 2025 |
| 573 | Crown Petroleum Company | Duncan, OK 73534-0938 | Oil & Gas Operator | Jan 2011 |
| 574 | Crude Oil Recovery Inc /Osage Only | | Oil & Gas Operator | Mar 2006 |
| 575 | Crude Resources | Sapulpa, OK 74066 | Oil & Gas Operator | Mar 2008 |
| 576 | Crumpton H A | Duncan, OK 73533 | Oil Operator | Dec 2002 |
| 577 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 578 | Crusader Energy Group Inc. | Austin, TX 78746 | Oil & Gas Operator | Mar 2015 |
| 579 | Crusader Energy Group LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2015 |
| 580 | Crusader Energy II LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 581 | Crusader Energy III LLC | Oklahoma City, OK 73142-1856 | Oil & Gas Operator | Feb 2011 |
| 582 | Crusher Oil Company | Ponca City, OK 74604-5612 | Oil Operator | Apr 2017 |
| 583 | Cruzen Drilling Company Inc | Cleveland, OK 74020-0470 | Oil Operator | Nov 2014 |
| 584 | Crystal Energy Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Feb 2019 |
| 585 | Csoda Operating Company LLC | Amarillo, TX 79114-7506 | Oil & Gas Operator | Aug 2021 |
| 586 | CSX Oil & Gas Corporation | Houston, TX 77210-4326 | Oil & Gas Operator | Mar 1993 |
| 587 | Cudd Operating Corp | Oklahoma City, OK 73118 | Oil & Gas Operator | Apr 2020 |
| 588 | Cuesta Petroleum Inc | Shawnee, OK 74801-6963 | Oil & Gas Operator | Dec 2025 |
| 589 | Culbreath Oil & Gas Co Inc | Tulsa, OK 74135 | Oil & Gas Operator | Jan 2026 |
| 590 | Culebra Oil & Gas, LLC | Kerrville, TX 78028 | Oil & Gas Operator | Mar 2026 |
| 591 | Culp & Copple Oil Company | Cushing, OK 74023 | Oil & Gas Operator | Nov 2025 |
| 592 | Cumberland Operating Company | Seminole, OK 74868-1258 | Oil & Gas Operator | Mar 2007 |
| 593 | Cummings Gene | | Oil Operator | Dec 2000 |
| 594 | Cummings Oil & Cattle | Ada, OK 74820-0994 | Oil Operator | Jan 2017 |
| 595 | Cummings Oil Company | Oklahoma City, OK 73112-6113 | Oil & Gas Operator | Jan 2026 |
| 596 | Cummins Wren Oil Company | Tulsa, OK 74135 | Oil & Gas Operator | Nov 1998 |
| 597 | Cundiff Harold | Perkins, OK 74059-4199 | Oil & Gas Operator | Dec 2025 |
| 598 | Cundiff Jack | Perkins, OK 74059-4198 | Oil & Gas Operator | Apr 2014 |
| 599 | Curn Lisa | Steubenville, OH 43952-2535 | Oil Operator | Dec 2025 |
| 600 | Curran Oil Co | Great Falls, MT 59401 | Gas Operator | May 2001 |