| 201 | Ridgeland Wyoming Inc | | Oil Operator | Dec 2014 |
| 202 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Apr 2024 |
| 203 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 204 | Rochelle Oil & Gas | Gillette, WY 82717 | Oil & Gas Operator | Jan 2024 |
| 205 | Rock Creek Resources LLC | Englewood, CO 80112 | Oil & Gas Operator | Dec 2021 |
| 206 | Rock Oil Corporation | Lawrence, KS 66046 | Oil Operator | Oct 2004 |
| 207 | Roemer Oil Company | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 208 | Ruby Drilling Company Inc | Gillette, WY 82718 | Oil Operator | Oct 2007 |
| 209 | Saba Energy Of Texas Inc | Houston, TX 77042 | Oil & Gas Operator | Jul 2007 |
| 210 | Sabine Production Company | | Oil & Gas Operator | Oct 1990 |
| 211 | Saxon Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Oct 2009 |
| 212 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 213 | Sharples Phillip T Trust | Denver, CO 80264 | Oil & Gas Operator | Nov 2020 |
| 214 | Signal Hill Company LLC | Cody, WY 82414 | Oil & Gas Operator | Mar 2024 |
| 215 | Six Bar Oil LLC | Pine Haven, WY 82721 | Oil Operator | Feb 2024 |
| 216 | Skinner Oil & Gas LLC | Gillette, WY 82717 | Oil & Gas Operator | Jan 2024 |
| 217 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2024 |
| 218 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Apr 2024 |
| 219 | Smith Conley P Operating Co | Eglewood, CO 80112-3640 | Oil & Gas Operator | Jun 2000 |
| 220 | Smokey Oil Company Inc | Casper, WY 82601 | Oil & Gas Operator | Dec 1996 |
| 221 | Snowy Owl LLC | Gillette, WY 82717 | Oil & Gas Operator | Mar 2024 |
| 222 | Southern Union Exploration | | Oil Operator | Jan 1990 |
| 223 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 224 | Southwestern Production Corporation | Lakewood, CO 80228 | Oil & Gas Operator | Mar 2024 |
| 225 | St Michael Exploration | | Oil & Gas Operator | Jun 1987 |
| 226 | Star Oil Operating Company LLC | Centennial, CO 80112 | Oil Operator | Jan 2024 |
| 227 | Star Resources LLC | Englewood, CO 80155-5185 | Oil & Gas Operator | Dec 2013 |
| 228 | Sterling Energy Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 1995 |
| 229 | Stone Petroleum Corporation | | Oil & Gas Operator | Dec 1996 |
| 230 | Stringer E M | | Oil Operator | May 1996 |
| 231 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |
| 232 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 233 | Tara Oil Company | | Oil Operator | Dec 1981 |
| 234 | Tbi Exploration Inc | Englewood, CO 801556525 | Oil & Gas Operator | Jun 2011 |
| 235 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Nov 2023 |
| 236 | Texaco Exploration & Prod | Midland, TX 79702 | Oil & Gas Operator | Aug 2002 |
| 237 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Apr 2024 |
| 238 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Jun 2018 |
| 239 | Timberline Production Company LLC | Casper, WY 82601 | Oil & Gas Operator | Oct 2020 |
| 240 | Torch Oil & Gas Company | Houston, TX 77010 | Oil & Gas Operator | Aug 1997 |
| 241 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 242 | Tresor Petroleum | | Oil & Gas Operator | Sep 1987 |
| 243 | Tri-Ex Corporation | | Oil & Gas Operator | Jan 1985 |
| 244 | Trinity Energy Resources Inc | Houston, TX 77079 | Oil & Gas Operator | Aug 2005 |
| 245 | Tripower Resources LLC | Ardmore, OK 73402 | Oil & Gas Operator | Apr 2024 |
| 246 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Mar 2024 |
| 247 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 248 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |
| 249 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 250 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 251 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Dec 2023 |
| 252 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2024 |
| 253 | Vast Oil Inc | Fullerton, CA 92832 | Oil & Gas Operator | Mar 2024 |
| 254 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2024 |
| 255 | Warren E & P Inc | Dallas, TX 75240 | Oil & Gas Operator | Dec 2023 |
| 256 | Washington Energy Exploration | | Oil & Gas Operator | Dec 1997 |
| 257 | Weaver Oil Inc | | Oil & Gas Operator | Oct 2011 |
| 258 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Feb 2024 |
| 259 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |
| 260 | Western American Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2023 |
| 261 | Western Gas Resources Inc | Denver, CO 80202-1955 | Oil & Gas Operator | Dec 2007 |
| 262 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2020 |
| 263 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Jan 2024 |
| 264 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 265 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Feb 2024 |
| 266 | Whisler Enterprise Company | Erie, CO 80516 | Oil & Gas Operator | Mar 2024 |
| 267 | White Rock Oil & Gas, LLC | Plano, TX 75024 | Oil & Gas Operator | Apr 2024 |
| 268 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Apr 2024 |
| 269 | Wichita River Oil Corporation | Englewood, CO 80111 | Oil & Gas Operator | Apr 2009 |
| 270 | Wildfire Partners Inc | Ardmore, OK 73402 | Oil & Gas Operator | Dec 2009 |
| 271 | Williams Ted H | | Oil & Gas Operator | Dec 2008 |
| 272 | Win Oil Company | Russell, KS 67665 | Oil & Gas Operator | Jul 2021 |
| 273 | Winter Ridge Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Sep 2011 |
| 274 | Wold Energy Partners LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2022 |
| 275 | Wood River Oil & Refining Co | | Oil & Gas Operator | Dec 1998 |
| 276 | WPX Energy Rocky Mountain LLC | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2024 |
| 277 | Wulf Oil Co | | Oil & Gas Operator | Dec 1984 |
| 278 | Wyoming Resources Corporation | Rapid City, SD 57702 | Oil & Gas Operator | Oct 2018 |
| 279 | Yates Drilling Company | Artesia, NM 88210 | Oil & Gas Operator | Dec 2021 |
| 280 | Yegen E C | Casper, WY 82604 | Oil & Gas Operator | Mar 2015 |