| 201 | Hawley Oil Company | Conrad, MT 59425-9802 | Oil Operator | Dec 2024 |
| 202 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 203 | Helis Oil & Gas Company, L.L.C. | New Orleans, LA 70130 | Oil & Gas Operator | Oct 2023 |
| 204 | Hell Creek Crude LLC | Winnett, MT 59087 | Oil Operator | Feb 2025 |
| 205 | Herco Exploration LLC | Billings, MT 59103 | Gas Operator | Oct 2024 |
| 206 | Highline Exploration, Inc. | Tuscaloosa, AL 35402 | Gas Operator | Nov 2020 |
| 207 | Hinto Energy, LLC | Edwards, CO 81632 | Oil Operator | Mar 2017 |
| 208 | Hofland, James D. | Kevin, MT 59454 | Oil & Gas Operator | Mar 2025 |
| 209 | Home-Stake Oil & Gas Company | Plano, TX 75093 | Oil & Gas Operator | Feb 2025 |
| 210 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 211 | HR Energy LLC | Shelby, MT 59474 | Oil & Gas Operator | Feb 2025 |
| 212 | HRC Operating, LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2017 |
| 213 | HS Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2005 |
| 214 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Apr 2025 |
| 215 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 216 | Humble Oil & Refining Co. | Houston, TX 77252 | Oil & Gas Operator | Jan 2000 |
| 217 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 218 | Huntington Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2006 |
| 219 | Intermountain Leasing, Inc. | Billings, MT 59103 | Gas Operator | Mar 2020 |
| 220 | Intermountain Operating, Inc. | Billings, MT 59103 | Oil & Gas Operator | Jul 2001 |
| 221 | Interstate Explorations LLC | Houston, TX 77010 | Oil & Gas Operator | Apr 2025 |
| 222 | Intoil, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Dec 2002 |
| 223 | J & G Operating | Shelby, MT 59474 | Oil & Gas Operator | Aug 2000 |
| 224 | J H Oil Company (James Hofland) | Kevin, MT 59454 | Oil & Gas Operator | Jun 2015 |
| 225 | J.H.R. Corporation | Bridgeville, PA 15017 | Oil & Gas Operator | Jul 2001 |
| 226 | J.J. Bunkirt Oil & Gas Corp. | Powell, WY 82435 | Oil & Gas Operator | Aug 2020 |
| 227 | Jake Oil, LLC | Billings, MT 59101 | Oil Operator | Feb 2022 |
| 228 | JN Expl & Prod LTD Partnership | Billings, MT 59103-0159 | Oil & Gas Operator | Feb 2001 |
| 229 | Journey Operating, L.L.C. | Sugar Land, TX 77496 | Oil & Gas Operator | Aug 2006 |
| 230 | Jurassic Resources Development Na LLC | Bismarck, ND 58504-5835 | Gas Operator | Feb 2025 |
| 231 | K2 America Corporation | Calgary, AB T3P 3S8 | Oil & Gas Operator | Nov 2017 |
| 232 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Apr 2025 |
| 233 | Karsted Operating, LLC | Billings, MT 59102 | Oil Operator | Feb 2025 |
| 234 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 235 | Keesun Corporation | Cut Bank, MT 59427 | Oil & Gas Operator | Feb 2025 |
| 236 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 237 | KGH Operating Company | Billings, MT 59115 | Oil & Gas Operator | Feb 2025 |
| 238 | King-Sherwood Oil | Condon, MT 59826 | Oil Operator | Feb 2025 |
| 239 | Kipling Energy Incorporated | Shelby, MT 59474 | Oil & Gas Operator | Jan 2011 |
| 240 | Kirkwood W C | Casper, WY 82602 | Oil & Gas Operator | May 2005 |
| 241 | Klabzuba Oil & Gas Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 2012 |
| 242 | Knaup, Harry J. & Lucille | Shelby, MT 59474 | Oil Operator | Oct 2023 |
| 243 | Kodiak Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Sep 2020 |
| 244 | Kraken Operating, LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |
| 245 | Kykuit Resources, LLC | Winifred, MT 59489 | Gas Operator | Mar 2021 |
| 246 | Lamamco Drilling Company | Skiatook, OK 74070 | Oil & Gas Operator | Jan 2025 |
| 247 | Lamarsa Corp. | Cut Bank, MT 59427 | Oil & Gas Operator | Jan 2025 |
| 248 | Legacy Reserves Operating LP | Denver, CO 80201 | Oil & Gas Operator | Apr 2025 |
| 249 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 250 | Lone Wolf Operating, LLC | Billings, MT 59108 | Oil & Gas Operator | Nov 2024 |
| 251 | Lowrance, Darrell A. | Cut Bank, MT 59427 | Oil Operator | Aug 2007 |
| 252 | Luff Exploration Company | Denver, CO 80203 | Oil & Gas Operator | Feb 2025 |
| 253 | Lyon, John J. | Bozeman, MT 59718 | Oil & Gas Operator | Jun 2022 |
| 254 | M K Oil Company | Gillette, WY 82717-3470 | Oil & Gas Operator | Feb 2025 |
| 255 | Mach Petroleum, Inc. | Tulsa, OK 74153 | Oil & Gas Operator | Nov 2014 |
| 256 | Macum Energy Inc | Billings, MT 59104 | Oil & Gas Operator | Aug 2021 |
| 257 | Main Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2009 |
| 258 | Makoil, Inc. | Lake Forest, CA 92630 | Oil & Gas Operator | Jul 2007 |
| 259 | Manuel Corporation | Wichita, KS 67206 | Oil & Gas Operator | Feb 2025 |
| 260 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Feb 2025 |
| 261 | Mbi Oil & Gas LLC | Dickinson, ND 58601 | Oil & Gas Operator | Feb 2025 |
| 262 | McCarthy, Lawrence J. | Plains, MT 59859-9215 | Oil & Gas Operator | Nov 2011 |
| 263 | McCullis Resources Co., Inc. | Littleton, CO 80161 | Oil & Gas Operator | Feb 2025 |
| 264 | McMinn Operating Company, Inc. | Hempstead, TX 77445 | Oil & Gas Operator | Apr 2025 |
| 265 | McOil Montana One LLC | Vancouver, BC V6Z2W5 | Gas Operator | Jul 2024 |
| 266 | MCR, LLC | Shelby, MT 59474 | Oil & Gas Operator | Jan 2025 |
| 267 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 268 | Medallion Petroleum, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2015 |
| 269 | Mercury Exploration Co | Fort Worth, TX 76104 | Oil & Gas Operator | Dec 2006 |
| 270 | Merit Energy Company | Dallas, TX 75240 | Oil & Gas Operator | Apr 2025 |
| 271 | Miami Oil Producers Inc | Reno, NV 89501 | Oil & Gas Operator | Dec 2012 |
| 272 | Midway Energy, LLC | Thermopolis, WY 82443 | Oil Operator | Feb 2025 |
| 273 | Miocene Oil & Gas, LTD. | Englewood, CO 80110 | Oil & Gas Operator | Apr 2025 |
| 274 | Misc Oil Co | Oilmont, MT 59466 | Oil Operator | Jan 2025 |
| 275 | Missouri Basin Well Service, Inc. | Belfield, ND 58622 | Oil & Gas Operator | Jan 2018 |
| 276 | Missouri River Royalty Corporation | Bismarck, ND 58504 | Oil & Gas Operator | Feb 2025 |
| 277 | Mogo Reagan, LLC | Cut Bank, MT 59427 | Oil & Gas Operator | Feb 2025 |
| 278 | Montalban Oil & Gas Operations, Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Feb 2025 |
| 279 | Montana Energy Company, LLC | McAllen, TX 78501 | Oil & Gas Operator | Dec 2024 |
| 280 | Montana Heartland LLC | Bismarck, ND 58504 | Oil & Gas Operator | Feb 2025 |
| 281 | Montana Land & Exploration, Inc. | Calgary, AB T2P 3E7 | Oil & Gas Operator | Apr 2019 |
| 282 | Montana Land & Mineral Co. | Billings, MT 59105 | Gas Operator | Jan 2025 |
| 283 | Montana Oil Field Acquisition I, LLC | Rutherford, NJ 07070 | Oil Operator | Jun 2016 |
| 284 | Montana Power Company | Butte, MT 59701 | Oil & Gas Operator | Apr 2002 |
| 285 | Montana Power Gas Company | | Oil & Gas Operator | Apr 2002 |
| 286 | Monte Grande Exploration, Inc. | Cut Bank, MT 59427 | Oil Operator | Oct 2000 |
| 287 | Morningstar Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2025 |
| 288 | Mountain Pacific General Inc. | Cut Bank, MT 59427 | Oil & Gas Operator | Jun 2022 |
| 289 | Mountain States Resources Inc | Cut Bank, MT 59427 | Oil & Gas Operator | Oct 2000 |
| 290 | Murex Petroleum Corporation | Humble, TX 77347 | Oil & Gas Operator | Feb 2025 |
| 291 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 292 | Mystique Resources Company | Aurora, CO 80016 | Oil & Gas Operator | Feb 2023 |
| 293 | Nadel And Gussman Rockies, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2012 |
| 294 | Nance Petroleum Corporation | Billings, MT 59103-7168 | Oil & Gas Operator | Nov 2007 |
| 295 | Natural Gas Processing Company | Worland, WY 82401 | Oil & Gas Operator | Mar 2025 |
| 296 | Nautilus Poplar LLC | Poplar, MT 59255 | Oil Operator | Feb 2025 |
| 297 | Navasota Resources LTD. | | Oil & Gas Operator | Sep 2002 |
| 298 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 299 | Neptune Operating LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |
| 300 | Nerdlihc Company, Inc. | Long Beach, CA 90815 | Oil & Gas Operator | Nov 2006 |