| 1901 | Collier, W. D. Ranch | Post, TX 79356 | Oil & Gas Operator | Jan 2012 |
| 1902 | Collin C W | | Gas Operator | Aug 1993 |
| 1903 | Collin C W Jr | | Oil Operator | Oct 2015 |
| 1904 | Collin Oil Operations LLC | | Oil Operator | Dec 2025 |
| 1905 | Collins & Ware, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2003 |
| 1906 | Collins Associates Inc | | Oil & Gas Operator | Mar 1987 |
| 1907 | Collins C R And Collins F Dba Collins Brothers Oil | | Oil & Gas Operator | Jul 2008 |
| 1908 | Collins Dillard Dba Dilco Oil Company | Mangum, OK 73554-4029 | Oil & Gas Operator | Mar 2025 |
| 1909 | Collins John B | | Oil Operator | Sep 1994 |
| 1910 | Collins Oil & Gas Corp | Roswell, NM 88202 | Oil & Gas Operator | Jul 2017 |
| 1911 | Collins Oil Co. | Bartlesville, OK 74006 | Oil & Gas Operator | Dec 2024 |
| 1912 | Collins Oil Comp | | Oil Operator | Apr 1995 |
| 1913 | Collins Oil, LLC | Ellinwood, KS 67526 | Oil Operator | Sep 2025 |
| 1914 | Collins Petroleum Inc | Bartlesville, OK 74006-7024 | Oil & Gas Operator | Apr 2005 |
| 1915 | Collins Resources, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Mar 2011 |
| 1916 | Collins, Dave | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2024 |
| 1917 | Collins, David A And Cole, Alexander B. | Bolivar, NY 14715 | Oil & Gas Operator | Dec 2024 |
| 1918 | Collins, Paul | Big Springs, WV 26137-0000 | Oil & Gas Operator | Dec 2021 |
| 1919 | Collins, Stephen M | | Oil Operator | Nov 2025 |
| 1920 | Collins-McGregor Operating Company | Marietta, OH 45750 | Oil & Gas Operator | Dec 2024 |
| 1921 | Colo Construction Co., Inc. | Abilene, TX 79602 | Oil Operator | Apr 2004 |
| 1922 | Colo Exploration Company, Inc. | Benbrook, TX 76126 | Oil & Gas Operator | Feb 2026 |
| 1923 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 1924 | Colonial Corporation | St Simons Island, GA 31522 | Oil & Gas Operator | Dec 2000 |
| 1925 | Colonial Energy Company Inc | Garland, TN 75045 | Oil & Gas Operator | Apr 2015 |
| 1926 | Colonial Hardwoods Inc | Luthersburg, PA 15848-3506 | Gas Operator | Dec 2019 |
| 1927 | Colonial Resources LLC | Edmond, OK 73003-3207 | Oil & Gas Operator | Aug 2019 |
| 1928 | Colorado Bluebonnet Energy Corp. | Englewood, CO 80112 | Oil & Gas Operator | Feb 2001 |
| 1929 | Colorado Crude E | | Oil Operator | Jan 1986 |
| 1930 | Colorado Drilling Company | Grand Junction, CO 81501 | Oil Operator | Jan 1990 |
| 1931 | Colorado Gas Compression Inc | Longmont, CO 80501-5868 | Oil & Gas Operator | Aug 2013 |
| 1932 | Colorado Interst | | Gas Operator | Aug 1995 |
| 1933 | Colorado Interstate Gas Co | Colorado Springs, CO 80944 | Oil & Gas Operator | Jul 2004 |
| 1934 | Colorado Interstate Gas Company LLC | Colorado Springs, CO 80944 | Oil & Gas Operator | Dec 2025 |
| 1935 | Colorado Oil & G | | Oil & Gas Operator | Oct 1987 |
| 1936 | Colorado Oil & Gas Corporation | | Oil & Gas Operator | Sep 1984 |
| 1937 | Colorado Oil Co., Inc. | | Oil & Gas Operator | Dec 1977 |
| 1938 | Colorado Pica Petro Corp | Cortez, CO 81321 | Oil & Gas Operator | Apr 2007 |
| 1939 | Colorado-Swanson Landing Oil & Gas, LLC | Kilgore, TX 75663 | Oil Operator | Feb 2026 |
| 1940 | Colossus Operating LLC | Kalispell, MT 59901 | Oil Operator | Sep 2025 |
| 1941 | Colotex Operating, LLC | Aurora, CO 80015 | Oil & Gas Operator | Feb 2026 |
| 1942 | Colpitt Brothers Oil | Collinsville, OK 74021 | Oil & Gas Operator | Apr 2020 |
| 1943 | Colpitt Brothers Operating Co | Collinsville, OK 74021 | Oil & Gas Operator | Nov 2025 |
| 1944 | Colpitt C H Drilling Co LLC | Collinsville, OK 74021-7107 | Oil Operator | Nov 2025 |
| 1945 | Colpitt Chas H Drilling Co | Collinsville, OK 74021-7105 | Oil & Gas Operator | Mar 2012 |
| 1946 | Colt Energy Inc | Iola, KS 66749 | Oil & Gas Operator | Sep 2025 |
| 1947 | Colt Energy Inco | | Oil & Gas Operator | Dec 1996 |
| 1948 | Colt Oil & Gas Co. | Abilene, TX 79601 | Oil Operator | Apr 2004 |
| 1949 | Colt Oil Company | Andrews, TX 79714 | Oil & Gas Operator | Feb 1996 |
| 1950 | Colt Oil Corporation | Smithville, WV 26178 | Oil & Gas Operator | Dec 2021 |
| 1951 | Colt Oil LLC | Sapulpa, OK 74066-1010 | Oil Operator | Nov 2025 |
| 1952 | Colt Operating Corporation | San Antonio, TX 78231 | Oil & Gas Operator | Aug 2003 |
| 1953 | Colt Production Corp. Inc. | | Oil & Gas Operator | Jul 1996 |
| 1954 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 1955 | Colter Operating Co | Horseshoe Bay, TX 78654 | Oil & Gas Operator | Nov 1997 |
| 1956 | Coltharp, Edward H | | Oil & Gas Operator | Dec 1970 |
| 1957 | Colton Limited Liability Co | | Oil & Gas Operator | Sep 2023 |
| 1958 | Coltrane Charles | | Oil Operator | Dec 1980 |
| 1959 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 1960 | Columbia Gas Dev. Corp. | | Oil & Gas Operator | Apr 1996 |
| 1961 | Columbia Gas Development | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 1962 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 1963 | Columbia Gas Trans LLC | Charleston, WV 25325-1273 | Gas Operator | Dec 1987 |
| 1964 | Columbia Gas Transmission, LLC | Charleston, WV 25314 | Oil & Gas Operator | Dec 2021 |
| 1965 | Columbia Gulf Transmission Co. | | Oil Operator | Dec 2014 |
| 1966 | Columbia Gulf Transmission Company, LLC | | Oil Operator | Jan 2025 |
| 1967 | Columbia Minerals Corp., Inc. | | Oil & Gas Operator | May 1996 |
| 1968 | Columbia Natural Res Inc | Charleston, WV 25362-0070 | Gas Operator | Dec 2008 |
| 1969 | Columbia Natural Resources, LLC | Charleston, WV 23502 | Oil & Gas Operator | Dec 2021 |
| 1970 | Columbia Oil Company, Inc | Guy, AR 72061 | Oil & Gas Operator | Jan 2025 |
| 1971 | Columbia Petrole | | Oil Operator | Sep 1988 |
| 1972 | Columbia Petroleum Corp. | | Oil & Gas Operator | Jun 1982 |
| 1973 | Columbia Petroleum LLC | Oyster Bay, NY 11771 | Oil & Gas Operator | Feb 2025 |
| 1974 | Columbia Petroleum, LTD. | Farmington, UT 84025 | Oil Operator | Nov 2025 |
| 1975 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 1976 | Columbian Production Corporation | Topeka, KS 66601 | Oil Operator | Oct 1999 |
| 1977 | Columbian Servic | | Oil & Gas Operator | Nov 1993 |
| 1978 | Columbian Services C | | Oil Operator | Jan 1992 |
| 1979 | Columbian Services Corporation | Topeka, KS 66603 | Gas Operator | Dec 2009 |
| 1980 | Columbine Associates | | Oil & Gas Operator | Dec 2025 |
| 1981 | Columbine Exploration Corp | Englewood, CO 80111 | Oil & Gas Operator | Aug 1998 |
| 1982 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 1983 | Columbus Energy, LLC | Houston, TX 77046 | Oil & Gas Operator | Feb 2026 |
| 1984 | Columbus III Production LC | | Oil Operator | Oct 2003 |
| 1985 | Columbus Oil And Gas LLC | | Oil Operator | Oct 2020 |
| 1986 | Columbus Oil Company | Seminole, OK 74868 | Oil & Gas Operator | Dec 2025 |
| 1987 | Columbus Oilfield Explor Co | Powell, OH 43065-9315 | Gas Operator | Dec 2004 |
| 1988 | Columbus Oilfield Exploration Company | Columbus, OH 43220 | Oil & Gas Operator | Dec 2013 |
| 1989 | Columbus Production Inc | | Oil & Gas Operator | Mar 2005 |
| 1990 | Comac Well Service, Inc. | Borger, TX 79008 | Oil & Gas Operator | Mar 2008 |
| 1991 | Comal Operating LLC | San Antonio, TX 78217 | Oil & Gas Operator | Feb 2026 |
| 1992 | Comanche Drilling Company | Cut Bank, MT 59427 | Oil & Gas Operator | Oct 2025 |
| 1993 | Comanche Exploration Co LLC | Oklahoma City, OK 73116-7334 | Oil & Gas Operator | Dec 2025 |
| 1994 | Comanche Exploration Company | Oklahoma City, OK 73120-2797 | Oil & Gas Operator | Feb 2007 |
| 1995 | Comanche Investments | Midland, TX 79706 | Oil & Gas Operator | Aug 1998 |
| 1996 | Comanche Oil & Gas Corp | Salt Lake City, UT 84107-3075 | Oil & Gas Operator | May 2005 |
| 1997 | Comanche Oil And Service, LLC | | Oil Operator | Nov 2025 |
| 1998 | Comanche Operating Co. | Oklahoma City, OK 73120 | Oil & Gas Operator | Aug 2002 |
| 1999 | Comanche Petroleum Corporation | Oklahoma City, OK 73179 | Oil & Gas Operator | Apr 2024 |
| 2000 | Comanche Product | | Oil & Gas Operator | Jan 1992 |