| 101 | Layton Oil Co | | Oil Operator | Feb 1994 |
| 102 | Lea Exploration, Inc. | | Oil & Gas Operator | Nov 1989 |
| 103 | Leads Resources, L.L.C. | | Oil & Gas Operator | Jan 2017 |
| 104 | Lear Gas Transmission | | Oil Operator | Aug 1989 |
| 105 | Lear Petroleum Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Aug 1999 |
| 106 | Leatherman Creek, Inc. | | Oil Operator | Jul 2001 |
| 107 | Lebus Oilfield Service Co | | Oil Operator | Sep 2009 |
| 108 | Lee Mills | | Oil Operator | Feb 1992 |
| 109 | Lee Roy Daigle | | Oil Operator | Dec 1992 |
| 110 | Leeward Operators LLC | | Oil & Gas Operator | Jul 2011 |
| 111 | Legacy Energy, LLC | Russell, KS 67665 | Oil Operator | Sep 2025 |
| 112 | Legacy Operating Company | | Oil & Gas Operator | Aug 1992 |
| 113 | Legacy Resources Co., L.P. | | Oil & Gas Operator | Apr 2019 |
| 114 | Legend Fund, LLC | | Oil & Gas Operator | Jan 2025 |
| 115 | Legendary Oil Co., Inc. | | Oil Operator | Feb 2004 |
| 116 | Legendary Well Service, Inc. | | Oil Operator | Jan 1996 |
| 117 | Leger Production Company, Inc. | | Oil & Gas Operator | Apr 1984 |
| 118 | Leggett Petroleum, L.L.C. | | Oil & Gas Operator | Dec 2020 |
| 119 | Leigh Operating Co | Dallas, TX 75205 | Oil & Gas Operator | Mar 2008 |
| 120 | Lenape Resources Corp | | Oil & Gas Operator | Dec 2000 |
| 121 | Lenert & Pettitt, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Sep 1994 |
| 122 | Leo Vesenmeir, Jr. | | Oil & Gas Operator | Jul 1987 |
| 123 | Leo Windham | | Oil Operator | Jul 1992 |
| 124 | Leroy W. & Charlie G. James | | Gas Operator | Oct 1979 |
| 125 | Leroy W. James | | Oil & Gas Operator | Oct 1991 |
| 126 | Leshen Energy USA LLC | | Oil Operator | Jan 2025 |
| 127 | Levi Gas Co., Inc. | | Gas Operator | Mar 2019 |
| 128 | Levinson Partners Corporation | Denver, CO 80202 | Oil & Gas Operator | Jul 1995 |
| 129 | Lewis & Manziel | | Oil Operator | Apr 1989 |
| 130 | Lewis Operating Company | Holliday, TX 76366 | Oil & Gas Operator | Feb 2026 |
| 131 | Lewis Williams | | Oil & Gas Operator | Feb 1991 |
| 132 | Lexico Exploration | | Oil Operator | Mar 1986 |
| 133 | LGS Exploration Program | | Gas Operator | Jul 1990 |
| 134 | LGS Exploration, Inc. | | Oil & Gas Operator | Jan 1991 |
| 135 | LHC Petroleum Corporation | | Oil & Gas Operator | Jul 2001 |
| 136 | Li'L Sugar Oil Company | | Oil Operator | Nov 2019 |
| 137 | Liberty Exploration Co. | | Oil Operator | Apr 1987 |
| 138 | Liberty Oil & Gas Co., Inc. | | Oil Operator | Feb 1991 |
| 139 | Liberty Oil & Gas Corp | Olney, IL 62450-2489 | Oil & Gas Operator | Dec 2021 |
| 140 | Liberty Operating Company,LLC | | Oil & Gas Operator | Jan 2026 |
| 141 | Liberty Resources, Inc. | | Oil & Gas Operator | Dec 2024 |
| 142 | Lighthouse Operating, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jun 2021 |
| 143 | Lightning Productions, Inc. | | Oil & Gas Operator | Mar 1990 |
| 144 | Lignum Oil Co | | Oil & Gas Operator | Dec 1989 |
| 145 | Limited Resources | Perryton, TX 79070 | Oil & Gas Operator | Aug 2003 |
| 146 | Lindenmuth & Associates | | Oil & Gas Operator | Aug 2001 |
| 147 | Linder Energy/La General Oil | | Oil & Gas Operator | Mar 1989 |
| 148 | Linder Oil Company | | Oil & Gas Operator | Apr 1985 |
| 149 | Linder Oil Company,A Partnership | Shreveport, LA 71136 | Oil & Gas Operator | Feb 2026 |
| 150 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 151 | Linn Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 152 | Linville Natural Gas Co. Inc. | | Gas Operator | Sep 2000 |
| 153 | Little & Whyte Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Mar 2008 |
| 154 | Littlefield Oil & Gas Company | | Oil & Gas Operator | Jan 1990 |
| 155 | Live Oak Energy, Inc. | | Oil & Gas Operator | Dec 2011 |
| 156 | Live Oak Petroleum, Inc. | Dallas, TX 75251 | Gas Operator | Mar 2001 |
| 157 | Lko Operating LLC | | Oil & Gas Operator | Feb 2017 |
| 158 | LL&N Oil & Gas Co., Inc. | | Oil Operator | Sep 1982 |
| 159 | Llog Expl. Co. | Metairie, LA 70005 | Oil & Gas Operator | Jan 2003 |
| 160 | Llog Expl. Co.-Biggs | | Oil Operator | Sep 1985 |
| 161 | Llog Exploration & Prod Co | | Oil & Gas Operator | Jul 2000 |
| 162 | Llog Exploration Company, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 163 | Llog Production Company | Metairie, LA 70005 | Oil & Gas Operator | Nov 2025 |
| 164 | Llox, L.L.C. | Covington, LA 70433 | Oil & Gas Operator | Feb 2026 |
| 165 | Lloyd E. Hargrove | | Oil & Gas Operator | Aug 1998 |
| 166 | Lloyd M McKenzie | | Oil Operator | Mar 2001 |
| 167 | LNG Gathering Company | | Oil Operator | Oct 2024 |
| 168 | Lobo Operating, Inc. | Houston, TX 77077 | Oil & Gas Operator | Dec 2024 |
| 169 | Loch Exploration, Inc. | | Oil & Gas Operator | Apr 1990 |
| 170 | Lock Arbor Production Co | | Gas Operator | Aug 1987 |
| 171 | Locust Ridge Gas Company | | Oil Operator | Mar 2003 |
| 172 | Loe Oil & Gas Corporation | | Gas Operator | Dec 1977 |
| 173 | Loe Pipe Yard, Inc. | | Oil & Gas Operator | Jan 1997 |
| 174 | Logue And Patterson, Inc. | | Oil & Gas Operator | Nov 1991 |
| 175 | Long Acres Prod. Co., Inc. | | Oil & Gas Operator | Aug 1986 |
| 176 | Long Bros. Oil Co. | | Oil Operator | Jul 2015 |
| 177 | Long Oil & Natural Gas Corp. | | Oil & Gas Operator | Feb 1996 |
| 178 | Long Oil And Gas Expl., LTD | | Oil & Gas Operator | Apr 1988 |
| 179 | Long Operating, L.L.C. | Shreveport, LA 71166 | Oil & Gas Operator | Jun 2006 |
| 180 | Long Trusts, The | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 181 | Longhorn Oil & Gas Company | | Oil & Gas Operator | Sep 1982 |
| 182 | Longleaf Gas & Oil | | Oil Operator | May 2010 |
| 183 | Longview Production, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2002 |
| 184 | Longville Production Co., Inc. | | Oil & Gas Operator | Sep 1995 |
| 185 | Lotter Gas Co., Inc. | | Gas Operator | Apr 2009 |
| 186 | Lou-Tex Oil & Gas Co. | | Oil & Gas Operator | Jun 1987 |
| 187 | Louis J. Roussel | | Oil & Gas Operator | Sep 1991 |
| 188 | Louisiana Crude Oil&Gas Co Inc | | Oil & Gas Operator | Mar 1984 |
| 189 | Louisiana Delta Oil Co, LLC | | Oil & Gas Operator | Nov 2024 |
| 190 | Louisiana Energy & Environmental, Inc. | | Oil & Gas Operator | Aug 2015 |
| 191 | Louisiana Energy Consultants, Inc. | | Oil & Gas Operator | Dec 2024 |
| 192 | Louisiana Energy Corp. | | Gas Operator | Dec 1987 |
| 193 | Louisiana Energy Investors, L.L.C. | | Oil & Gas Operator | Jun 2016 |
| 194 | Louisiana Fuel Oil Corporation | | Oil Operator | Aug 1997 |
| 195 | Louisiana Gas Development Corp | | Oil & Gas Operator | Jan 2025 |
| 196 | Louisiana Gas Production Co | | Gas Operator | Dec 1996 |
| 197 | Louisiana Gas Service Co. | | Oil Operator | May 2004 |
| 198 | Louisiana Gas System, Inc. | | Oil Operator | Apr 2004 |
| 199 | Louisiana General Petr. Corp. | | Oil & Gas Operator | Mar 1980 |
| 200 | Louisiana Intrastate Gas Corp. | | Oil Operator | Feb 1994 |