Oil & Gas Companies in Hidalgo County, TX
| Company Name | Company Location | Company Type | Most Recent Production |
| 1 | O'Benco, Inc. | Shreveport, LA 71136 | Oil & Gas Operator | Oct 2025 |
| 2 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 3 | Ocean Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 4 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 5 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Oct 2025 |
| 6 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 7 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Oct 2025 |
| 8 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 9 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 10 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |
| 11 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Oct 2025 |
Production numbers shown above are only for Hidalgo County, TX and for the production period listed.