| 1101 | Ranger Holdings Co | | Oil & Gas Operator | Jul 1993 |
| 1102 | Rangeview Resources Operating Co | | Oil & Gas Operator | Jan 2026 |
| 1103 | Rathbun Roger | | Oil & Gas Operator | Dec 1993 |
| 1104 | Rathpro Inc | Douglas, WY 82633 | Oil & Gas Operator | Feb 1994 |
| 1105 | RB Operating Company | Shawnee, OK 74802-1488 | Oil & Gas Operator | Apr 2015 |
| 1106 | RDG Oil & Gas LLC | Post Falls, ID 82854 | Oil & Gas Operator | Mar 2017 |
| 1107 | Reading & Bates Petroleum | | Oil & Gas Operator | Apr 1989 |
| 1108 | Red River Oil & Gas LLC | Cherry Hills, CO 80110 | Oil & Gas Operator | Feb 2025 |
| 1109 | Red Rock Resources Corporation | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Feb 2026 |
| 1110 | Red Tiger Oil & Gas LLC | Gillette, WY 82718 | Oil & Gas Operator | Jan 2026 |
| 1111 | Redbud E & P, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Apr 2026 |
| 1112 | Redstone Gas Partners LLC | Denver, CO 80202 | Gas Operator | Mar 2001 |
| 1113 | Redstone Resources Inc | Newcastle, WY 82701 | Gas Operator | Dec 2010 |
| 1114 | Reef Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2007 |
| 1115 | Reliance Resources Inc | Houston, TX 77007 | Gas Operator | Jun 2012 |
| 1116 | Remuda Energy Development LLC | Billings, MT 59104 | Oil & Gas Operator | Feb 2026 |
| 1117 | Renor Exploration | Englewood, CO 80111 | Oil Operator | Feb 2001 |
| 1118 | Renos Land & Minerals Company | Casper, WY 82601 | Oil & Gas Operator | Oct 2021 |
| 1119 | Reserve Oil & Gas Company | | Oil & Gas Operator | Jul 1981 |
| 1120 | Reserve Operating Corp. | Houston, TX 77040 | Oil & Gas Operator | Apr 2026 |
| 1121 | Resolute Wyoming Inc | Denver, CO 80203 | Oil & Gas Operator | May 2018 |
| 1122 | Resource Enterprises Inc | Salt Lake City, UT 84108 | Gas Operator | Dec 1990 |
| 1123 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 1124 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 1125 | Rex Energy Rockies LLC | State College, PA 16801 | Oil & Gas Operator | May 2013 |
| 1126 | Riata Energy, Inc. | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2006 |
| 1127 | Richardson Oil Company | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2003 |
| 1128 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Feb 2026 |
| 1129 | Ridge Energy Partners LLC | Casper, WY 82601 | Oil Operator | Dec 2018 |
| 1130 | Ridgeland Wyoming Inc | | Oil Operator | Dec 2014 |
| 1131 | Rim Operating, Inc. | Englewood, CO 80112 | Oil & Gas Operator | Apr 2026 |
| 1132 | Rio Blanco Energy, Inc. | Littleton, CO 80121 | Oil & Gas Operator | Oct 2002 |
| 1133 | River City Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Nov 1997 |
| 1134 | River Gas Corporation | Tuscaloosa, AL 35406-2233 | Gas Operator | Dec 2000 |
| 1135 | Rki Exploration & Production LLC | Tulsa, OK 74172 | Oil & Gas Operator | Apr 2026 |
| 1136 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 1137 | Robert Hawkins Inc | Kevin, MT 59454 | Oil & Gas Operator | Feb 2026 |
| 1138 | Rochelle Oil & Gas | Gillette, WY 82717 | Oil & Gas Operator | Mar 2024 |
| 1139 | Rock Creek Resources LLC | Englewood, CO 80112 | Oil & Gas Operator | Dec 2021 |
| 1140 | Rock Oil Corporation | Lawrence, KS 66046 | Oil Operator | Oct 2004 |
| 1141 | Rock River Operating Inc | Laramie, WY 82070 | Oil & Gas Operator | Jan 2026 |
| 1142 | Rockies Resources Holdings LLC | Lakewood, CO 80228 | Oil & Gas Operator | Feb 2026 |
| 1143 | Rocky Mountain Gas Inc | Sheridan, WY 82801 | Gas Operator | Nov 2009 |
| 1144 | Roemer Oil Company | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 1145 | Roff Operating Company LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 1146 | Ronadero Company Inc | Roswell, NM BAD ADDR | Oil & Gas Operator | Dec 1996 |
| 1147 | Rosa Petroleum | Evansville, WY 82636 | Oil Operator | Dec 1995 |
| 1148 | Royal Oil LLC | Flower Mound, TX 75028 | Oil Operator | Dec 2015 |
| 1149 | Royal Resources Exploration | | Oil & Gas Operator | Mar 1984 |
| 1150 | Ruby Drilling Company Inc | Gillette, WY 82718 | Oil Operator | Oct 2007 |
| 1151 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 1152 | Saba Energy Of Texas Inc | Houston, TX 77042 | Oil & Gas Operator | Jul 2007 |
| 1153 | Sabine Corporation | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 1996 |
| 1154 | Sabine Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 1155 | Saga Petroleum LLC Of Colorado | Norman, OK 73072 | Oil & Gas Operator | Apr 2026 |
| 1156 | Sage Butte PRB Operating, LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 1157 | Sage Petroleum LLC | Casper, WY 82601 | Oil Operator | Jun 2008 |
| 1158 | Salt Creek Operating LLC | FT Morgan, CO 80701 | Oil & Gas Operator | Mar 2020 |
| 1159 | Salt Creek West Partners | | Oil Operator | Jul 1995 |
| 1160 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 1161 | Samson Exploration LLC | Tulsa, OK 74101 | Oil & Gas Operator | Feb 2026 |
| 1162 | Samson Oil & Gas USA Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 1163 | Samson Resources Company LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2021 |
| 1164 | San Marco Petroleum Inc | Denver, CO 80293 | Oil & Gas Operator | Dec 2025 |
| 1165 | Sanchez-O'Brien | | Oil & Gas Operator | Dec 1984 |
| 1166 | Sands Oil Company Inc | Billings, MT 59103 | Oil & Gas Operator | Feb 2026 |
| 1167 | Sands-American Corp | | Oil & Gas Operator | Jan 1990 |
| 1168 | Santa Rosa Petroleum LLC | Recluse, WY 82725 | Oil & Gas Operator | Feb 2026 |
| 1169 | Sauer Bill Oil & Gas Company LLC | Casper, WY 82604 | Oil & Gas Operator | Jun 1999 |
| 1170 | Saxon Oil Company | Dallas, TX 75204 | Oil & Gas Operator | Oct 2009 |
| 1171 | Sayers Operating Company | Midland, TX 79705 | Oil & Gas Operator | Feb 2005 |
| 1172 | Scana Petroleum Resources Inc | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 1173 | Scarlett Energy Enterprises LLC | Watchung, NJ 07069 | Oil & Gas Operator | Oct 2014 |
| 1174 | Sceptre Resources Inc | | Oil & Gas Operator | Dec 2007 |
| 1175 | Schiff & Jackson Oil Producers | Dallas, TX 75206 | Oil & Gas Operator | Feb 2026 |
| 1176 | Schlaikjer A L | | Oil Operator | Feb 1997 |
| 1177 | Schmid Properties, Inc. | Hico, TX 76457 | Oil & Gas Operator | Apr 2026 |
| 1178 | Schneider Oil Corporation | Broomfield, CO 80020 | Oil & Gas Operator | Aug 2009 |
| 1179 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 1180 | Seahawk Oil International Inc | Newport Beach, CA 92660 | Oil & Gas Operator | Oct 1997 |
| 1181 | Seedy Draw LLC | Greenwood VIllage, CO 80111 | Oil Operator | Jan 2026 |
| 1182 | Seer Operating LLC | Sheridan, WY 82801 | Oil & Gas Operator | Oct 2016 |
| 1183 | Seguro Oil & Gas Inc | | Oil Operator | Jul 1992 |
| 1184 | Sendero Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2026 |
| 1185 | Seven Sisters Oil & Gas LLC | Casper, WY 82602 | Oil & Gas Operator | Jan 2022 |
| 1186 | Sgcu GP LLC | Casper, WY 82602 | Oil Operator | Jan 2026 |
| 1187 | Shar Alan Oil Company | | Oil & Gas Operator | Oct 2005 |
| 1188 | Sharkey Well Service Inc | | Oil Operator | Dec 2023 |
| 1189 | Sharples Phillip T Trust | Denver, CO 80264 | Oil & Gas Operator | Nov 2020 |
| 1190 | Shelco | Maysville, MO 64469 | Oil & Gas Operator | May 2021 |
| 1191 | Shell Rocky Mountain Production LLC | Pinedale, WY 82941 | Oil & Gas Operator | Dec 2008 |
| 1192 | Shenandoah Energy Inc | Denver, CO 80265-1050 | Oil & Gas Operator | Dec 2014 |
| 1193 | Shenandoah Oil Corporation | | Oil & Gas Operator | Jun 1979 |
| 1194 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2026 |
| 1195 | Siegfried R H Inc | Tulsa, OK 74104 | Oil & Gas Operator | Mar 2008 |
| 1196 | Sierra Trading Corporation | | Oil & Gas Operator | Sep 1978 |
| 1197 | Signal Hill Company LLC | Cody, WY 82414 | Oil & Gas Operator | Dec 2024 |
| 1198 | Signal Hill Operating LLC | | Oil & Gas Operator | Feb 2026 |
| 1199 | Silverado Oil Inc | Greeley, CO 80631 | Oil Operator | Apr 2000 |
| 1200 | Simasko Production Co | Denver, CO 80204 | Oil & Gas Operator | Nov 1997 |