Marathon Oil Corporation was an American company engaged in hydrocarbon exploration. In November 2024, it was acquired by ConocoPhillips and absorbed into the company.
Marathon was founded in 1887 in Lima, Ohio, as the Ohio Oil Company. In 1899, the company was acquired by the Standard Oil Company (New Jersey). After the antitrust case against Jersey Standard in 1911 and subsequent breakup of its holdings, Ohio Oil once again became an independent company. In 1930, Ohio Oil acquired the Transcontinental Oil Company, which operated the "Marathon" brand of retail fuel stations. Ohio Oil continued to use the Marathon brand, and in 1962, Ohio changed its name to the Marathon Oil Company.
In January 1982, Marathon was acquired by U.S. Steel.