| 201 | Ciris Energy Inc | Centennial, CO 80112 | Gas Operator | Dec 2016 |
| 202 | Cirque Resources LP | Denver, CO 80202 | Oil & Gas Operator | Aug 2016 |
| 203 | Citation Oil & Gas Corp | Houston, TX 77269 | Oil & Gas Operator | Sep 2026 |
| 204 | CKT Energy LLC | Dallas, TX 75379 | Oil & Gas Operator | Sep 2020 |
| 205 | Clark Oil & Gas Inc | | Oil & Gas Operator | Dec 1990 |
| 206 | Clark Oil Producing Company | | Oil & Gas Operator | Oct 1979 |
| 207 | CLC Operations Inc | Midland, TX 79701 | Oil & Gas Operator | Mar 1997 |
| 208 | Cline Production Company | Billings, MT 59104 | Oil & Gas Operator | Jun 2026 |
| 209 | Clinton Oil Company | Wichita, KS 67202 | Oil & Gas Operator | Apr 1980 |
| 210 | Cloud Peak Operating LLC | Casper, WY 82601 | Oil Operator | Jun 2026 |
| 211 | CMS Oil And Gas Company | Jackson, MI 49201 | Oil & Gas Operator | Oct 2002 |
| 212 | CNX Gas Company LLC | Canonsburg, PA 15317 | Oil & Gas Operator | Jun 2026 |
| 213 | Coal Creek Minerals LLC | Northglenn, CO 80234 | Gas Operator | Feb 2012 |
| 214 | Coaleum Corporation | Dallas, TX 75205 | Oil & Gas Operator | Jan 2001 |
| 215 | Coastal Chem Inc | Midvale, UT 84047 | Oil & Gas Operator | Aug 2003 |
| 216 | Coastal Oil & Gas Corp | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 217 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2026 |
| 218 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Jul 2026 |
| 219 | Cohort Energy Company | Centennial, CO 80112 | Oil & Gas Operator | Feb 2007 |
| 220 | Coleman Oil & Gas Inc | Farmington, NM 87499 | Oil & Gas Operator | Jan 2023 |
| 221 | Colorado Oil & Gas Corporation | | Oil & Gas Operator | Sep 1984 |
| 222 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 223 | Coltrane Charles | | Oil Operator | Dec 1980 |
| 224 | Columbine Exploration Corp | Englewood, CO 80111 | Oil & Gas Operator | Aug 1998 |
| 225 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 226 | Columbus Production Inc | | Oil & Gas Operator | Mar 2005 |
| 227 | Comanche Oil & Gas Corp | Salt Lake City, UT 84107-3075 | Oil & Gas Operator | May 2005 |
| 228 | Combined Oil & Gas | Denver, CO 80202 | Oil & Gas Operator | Feb 1990 |
| 229 | Comdisco Exploration Inc | | Oil Operator | Dec 1990 |
| 230 | Comet Energy Services LLC | Traverse City, MI 49686 | Oil & Gas Operator | Oct 2011 |
| 231 | Common Energy Inc | Douglas, WY 82633 | Oil & Gas Operator | Aug 1995 |
| 232 | Condor Exploration LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Sep 2009 |
| 233 | Conoco Inc | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 234 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Sep 2026 |
| 235 | Conquest Exploration | Houston, TX 77068 | Oil & Gas Operator | May 1991 |
| 236 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 237 | Contango Resources LLC | Andrews, TX 79714 | Oil & Gas Operator | Jul 2026 |
| 238 | Contango Rocky Mountain Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2020 |
| 239 | Continental Industries LC | Casper, WY 82602 | Oil & Gas Operator | Feb 2008 |
| 240 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 241 | Continental Production Co LLC | Greenwood VIllage, CO 80155 | Oil & Gas Operator | Aug 2012 |
| 242 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | Sep 2026 |
| 243 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 244 | Cook D L | Holliday, TX 76366 | Oil & Gas Operator | Dec 2008 |
| 245 | Coquina Oil Corporation | Houston, TX 77227 | Oil & Gas Operator | Mar 2015 |
| 246 | Coral Production Corporation | Denver, CO 80201 | Oil & Gas Operator | Apr 2026 |
| 247 | Cordero Mining Co | Gillette, WY 82717 | Oil Operator | Nov 2009 |
| 248 | Cordero Oil And Gas LLC | Gillette, WY 82716 | Oil Operator | Nov 2021 |
| 249 | Cordillera Corporation | Denver, CO 80237 | Oil & Gas Operator | Feb 1996 |
| 250 | Cork Petroleum Corporation | Thermopolis, WY 82443 | Oil & Gas Operator | Apr 2012 |
| 251 | Cornerstone Natural Resources LLC | Denver, CO 80234 | Oil & Gas Operator | Jun 2026 |
| 252 | Coronado Oil Company | Denver, CO 80202 | Oil & Gas Operator | Dec 2019 |
| 253 | Corrida Oil Inc | Denver, CO 80217 | Oil & Gas Operator | Jun 1990 |
| 254 | Costilla Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 255 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 256 | Cottonwood Oil Inc | Worland, WY 82401 | Oil & Gas Operator | Jun 1988 |
| 257 | Cowan Oil Company | | Oil Operator | Sep 1990 |
| 258 | Cowboy Clean Fuels LLC | Laramie, WY 82072 | Gas Operator | Jun 2026 |
| 259 | Cox Edwin L & Berry R | | Oil & Gas Operator | Oct 1987 |
| 260 | Cox Kendall Jay | Recluse, WY 28775 | Oil & Gas Operator | Aug 2016 |
| 261 | CR Energy | | Oil & Gas Operator | Dec 1992 |
| 262 | Cramer Oil Company | Denver, CO 80202 | Oil Operator | Aug 2012 |
| 263 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2026 |
| 264 | Creek Oil Company | Colorado Springs, CO 80906 | Oil & Gas Operator | Aug 2001 |
| 265 | Crest Resources Inc | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2026 |
| 266 | Crowheart Energy LLC | Baggs, WY 82321 | Oil & Gas Operator | Jun 2026 |
| 267 | Crown Central Petroleum Corp | Richmond, TX 77469 | Oil & Gas Operator | Dec 1999 |
| 268 | Crown Energy Partners LLC | Englewood, CO 80112 | Oil & Gas Operator | Sep 2013 |
| 269 | Crown Oil & Gas Co Inc | Labarge, WY 83123 | Oil & Gas Operator | Jan 2023 |
| 270 | Crystal Exploration & Production Company | Shreveport, LA 71120 | Oil & Gas Operator | Feb 1995 |
| 271 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 272 | Cumberland Operating LLC | Cody, WY 82414 | Oil & Gas Operator | Jul 2026 |
| 273 | Czar Resources Inc | Houston, TX 77060 | Oil & Gas Operator | Oct 1992 |
| 274 | D & B Oil Company | Graham, TX 76450 | Oil & Gas Operator | Sep 2026 |
| 275 | D & D Contract Pumping Inc | Casper, WY 82604 | Oil Operator | Jul 2026 |
| 276 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Sep 2026 |
| 277 | D K Cook Heirs LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2011 |
| 278 | D90 Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Sep 2026 |
| 279 | Dahill Murray P | Casper, WY 82601 | Oil & Gas Operator | Jun 2007 |
| 280 | Dalen Resources Oil & Gas Co | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 281 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 282 | Darrah John Jay Jr | Wichita, KS 67201 | Oil & Gas Operator | Jul 2026 |
| 283 | Daube Company The | Ardmore, OK 73401 | Oil & Gas Operator | Jul 2026 |
| 284 | Davey Corporation | Golden, CO 80401 | Oil & Gas Operator | Jul 2026 |
| 285 | Davis & Tharel | | Oil & Gas Operator | Dec 1988 |
| 286 | Davis Bobby J | Upton, WY 82730 | Oil & Gas Operator | Oct 1989 |
| 287 | Davis Exploration | | Oil Operator | Dec 2007 |
| 288 | Davis Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 1988 |
| 289 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Sep 2026 |
| 290 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 291 | DCD Inc | Gillette, WY 82716 | Oil & Gas Operator | Aug 2003 |
| 292 | Debord Oil Producers | Lincoln, NE 68503 | Oil Operator | Dec 1998 |
| 293 | Deca Energy Corporation | | Oil & Gas Operator | Aug 1986 |
| 294 | Decalta International Corp | Denver, CO 80202 | Oil & Gas Operator | Mar 2015 |
| 295 | Degaugh Well Service Inc | | Oil Operator | Jul 1989 |
| 296 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 297 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Sep 2026 |
| 298 | Denbury Onshore, LLC | Spring, TX 77389 | Oil & Gas Operator | Sep 2026 |
| 299 | Department Of Energy | Casper, WY 82601 | Oil & Gas Operator | Jan 2015 |
| 300 | Deuel Arch W | | Oil & Gas Operator | Aug 1995 |