| 1001 | High Plains Oil | | Oil Operator | Jun 1989 |
| 1002 | High Plains Operating Co | | Oil & Gas Operator | Nov 1993 |
| 1003 | High Plains Operating, LLC | | Oil Operator | Sep 2025 |
| 1004 | High Plains Petroleum Corp | Boulder, CO 80305 | Oil & Gas Operator | Jan 2021 |
| 1005 | High Plains Production, LLC | Murray, KY 42071 | Oil & Gas Operator | Dec 2024 |
| 1006 | High Point Produ | | Gas Operator | May 1996 |
| 1007 | High River Res Operating, LLC | Dallas, TX 75219 | Oil & Gas Operator | Oct 2025 |
| 1008 | High River Resources Operating LLC | Farmington, NM 87401 | Oil & Gas Operator | Jul 2025 |
| 1009 | High Sierra Operating, LTD. | Canyon Lake, TX 78133 | Oil & Gas Operator | Mar 2008 |
| 1010 | High Sierra Water Services Mid Continent LLC | Denver, CO 80209 | Oil Operator | Feb 2010 |
| 1011 | High Sky Oil & Gas | Midland, TX 79705 | Oil & Gas Operator | Jun 2008 |
| 1012 | High Sky Partners LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2015 |
| 1013 | High Splint Gas & Oil, Inc | Greenville, KY 42345 | Oil Operator | Dec 2023 |
| 1014 | High Summit Oil & Gas Inc | | Oil & Gas Operator | Sep 1987 |
| 1015 | High-Hope Oil And Gas, Inc | | Oil & Gas Operator | Mar 2017 |
| 1016 | High-Line Production Services LLC | | Oil & Gas Operator | May 2025 |
| 1017 | Higher Standard Oil Company,Inc. | Frisco, TX 75034 | Oil Operator | Oct 2025 |
| 1018 | Highfill Bob W | Claremore, OK 74018-2595 | Oil Operator | Jun 2005 |
| 1019 | Highground, Inc. | Abilene, TX 79605 | Oil & Gas Operator | Oct 2025 |
| 1020 | Highhouse James R | Warren, PA 16365-7550 | Oil & Gas Operator | Dec 2008 |
| 1021 | Highland Exploration | | Oil Operator | Sep 1979 |
| 1022 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 1023 | Highland Oil & Gas Co | Mason, OH 45040 | Oil Operator | Dec 2022 |
| 1024 | Highland Oil & Gas LLC | Houston, TX 77079-7220 | Oil & Gas Operator | Feb 2015 |
| 1025 | Highland Oil Co. | | Oil Operator | Mar 1953 |
| 1026 | Highland Production Company | Midland, TX 79701 | Oil & Gas Operator | Mar 1996 |
| 1027 | Highland Resources, Inc. | | Oil & Gas Operator | Dec 2004 |
| 1028 | Highlander Oil & Gas Assets LLC | | Gas Operator | Jan 2025 |
| 1029 | Highlands Operating Co., Inc. | | Oil & Gas Operator | May 1990 |
| 1030 | Highline Exploration, Inc. | Tuscaloosa, AL 35402 | Gas Operator | Nov 2020 |
| 1031 | Highman Oil & Gas LLC | Woodsfield, OH 43793 | Oil & Gas Operator | Dec 2024 |
| 1032 | Highmark Energy Operating, LLC | Dallas, TX 75222 | Oil & Gas Operator | Oct 2025 |
| 1033 | Highmount Black Warrior Basin, LLC | | Gas Operator | Jul 2010 |
| 1034 | Highmount Expl & Prod Texas LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2014 |
| 1035 | Highmount Midwest Energy LLC | | Oil & Gas Operator | Sep 2011 |
| 1036 | Highmount Operating LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2014 |
| 1037 | Highpeak Energy Holdings, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 1038 | Highpoint Energy LLC | | Oil & Gas Operator | Nov 2022 |
| 1039 | Highpointe Oil & Gas LLC | Indiana, PA 15701-8944 | Gas Operator | Dec 2024 |
| 1040 | Hightower Energy LLC | Cushing, OK 74023-6370 | Oil & Gas Operator | Jun 2025 |
| 1041 | Hightower Exploration | Kilgore, TX 75662 | Oil & Gas Operator | Oct 2025 |
| 1042 | Hightower Oil & Gas | Cairo, IL 62914-0401 | Oil Operator | Nov 2014 |
| 1043 | Highway 15 SWD LLC | Shattuck, OK 73858 | Oil Operator | Oct 2021 |
| 1044 | Highway 60 SWD LLC | Shattuck, OK 73858-0848 | Oil Operator | Jul 2019 |
| 1045 | Hikcott Oil | Wilson, OK 73463-6537 | Oil Operator | Jan 2014 |
| 1046 | Hiko Bell Mining & Oil Co | Vernal, UT 84078 | Oil & Gas Operator | Oct 2003 |
| 1047 | Hilbers Oil & Gas | Archer City, TX 76351 | Oil & Gas Operator | Oct 2002 |
| 1048 | Hilburn Ind., Inc. | | Oil Operator | Jan 1978 |
| 1049 | Hilcorp Alaska, LLC | | Oil & Gas Operator | Aug 2025 |
| 1050 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Oct 2025 |
| 1051 | Hilcorp North Slope, LLC | | Oil & Gas Operator | Aug 2025 |
| 1052 | Hilden Oil Co Inc | | Oil & Gas Operator | Oct 2024 |
| 1053 | Hildreth, Roy G & Son Inc | Spencer, WV 25276 | Oil & Gas Operator | Dec 2021 |
| 1054 | Hildreth, Va Roy | | Oil & Gas Operator | Dec 1996 |
| 1055 | Hildreth, William H & David Dale | | Oil & Gas Operator | Dec 2021 |
| 1056 | Hill Drilling Inc | Millersburg, OH 44654 | Oil & Gas Operator | Dec 1997 |
| 1057 | Hill Gilford | Stroud, OK 74079-9401 | Oil & Gas Operator | May 2013 |
| 1058 | Hill John H | Dallas, TX 75240-7077 | Oil & Gas Operator | Jul 2015 |
| 1059 | Hill Oil And Gas Co., Inc. | Overland Park, KS 66213 | Oil Operator | Mar 2020 |
| 1060 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Jun 2025 |
| 1061 | Hill Operating LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Nov 2023 |
| 1062 | Hill Production | | Oil & Gas Operator | Nov 1981 |
| 1063 | Hill Production Co Inc-Wisconsin | Humble, TX 77347 | Oil & Gas Operator | Jun 1993 |
| 1064 | Hill Production Company | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2009 |
| 1065 | Hill Production Company No. 2 | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 1066 | Hill Resources Inc | | Oil & Gas Operator | Nov 2022 |
| 1067 | Hill Robert H & Willa F | Morris, OK 74445 | Oil & Gas Operator | Apr 2020 |
| 1068 | Hill William F | Millersburg, OH 44654 | Oil & Gas Operator | Dec 1993 |
| 1069 | Hill William H | Broken Arrow, OK 74012-8952 | Oil & Gas Operator | Apr 2020 |
| 1070 | Hill, A G | Dallas, TX 75201 | Oil & Gas Operator | May 2008 |
| 1071 | Hill, Albert, Trust | Dallas, TX 75201 | Oil & Gas Operator | May 2008 |
| 1072 | Hill, Bill | Kilgore, TX 75663 | Oil Operator | Mar 2014 |
| 1073 | Hill, Charles Drilling, Inc. | Grand Prairie, TX 75052 | Oil & Gas Operator | Oct 2025 |
| 1074 | Hill, Gillman A | Englewood, CO 80112 | Oil & Gas Operator | Jun 1993 |
| 1075 | Hill, Hub, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jan 1994 |
| 1076 | Hill, R.M. Operating Inc. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 1077 | Hill, T. R. | Graham, TX 76450 | Oil & Gas Operator | Apr 1995 |
| 1078 | Hill-Lake Gas Storage, L.P. | Houston, TX 77057 | Oil & Gas Operator | Aug 2010 |
| 1079 | Hill-Lake Gas Storage, LLC | Tulsa, OK 74172 | Oil & Gas Operator | Oct 2025 |
| 1080 | Hillary Oil Comp | | Oil & Gas Operator | Apr 1991 |
| 1081 | Hillcrest Petroleum, LLC | Midland, TX 79707 | Oil & Gas Operator | Jun 2019 |
| 1082 | Hillenburg Oil C | | Oil Operator | Apr 1994 |
| 1083 | Hillenburg Oil Co., A General Partnership | Broken Arrow, OK 74011 | Oil Operator | Jun 2025 |
| 1084 | Hillenburg Oil Company | Broken Arrow, OK 74011-4021 | Oil Operator | Apr 2011 |
| 1085 | Hilliard Oil | Bronte, TX 76933 | Oil & Gas Operator | Mar 2008 |
| 1086 | Hilliard Oil & Gas Inc | New Orleans, LA 70112 | Oil & Gas Operator | May 2001 |
| 1087 | Hilliard Petroleum Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 2009 |
| 1088 | Hilliker Oil Com | | Oil Operator | Jul 1984 |
| 1089 | Hilliker Production | Indian Wells, CA 92210 | Oil & Gas Operator | Jul 2007 |
| 1090 | Hillin Prod. Co. | Odessa, TX 79760 | Oil & Gas Operator | Apr 2002 |
| 1091 | Hillin Simon/Prime Expl., L.C. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 1092 | Hillin, T. A. | Kerrville, TX 78028 | Oil & Gas Operator | Aug 2020 |
| 1093 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 1094 | Hills Dozer Service | Stroud, OK 74079 | Oil & Gas Operator | Mar 2022 |
| 1095 | Hillside Oil & Gas, LLC | Midland, TX 79708 | Oil & Gas Operator | Apr 2016 |
| 1096 | Hillside Oil Inc | Aurora, ON L4G | Oil Operator | Dec 2021 |
| 1097 | Hillside Oil Partners | | Oil & Gas Operator | Dec 1999 |
| 1098 | Hillside Resources | Bartlesville, OK 74005 | Oil & Gas Operator | Jan 2007 |
| 1099 | Hilltex Operating Company, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jul 2021 |
| 1100 | Hilltop Development Corp | Frazeysburg, OH 43822 | Oil & Gas Operator | Dec 1984 |