Marathon Marathon is now two independent energy companies: Marathon Oil Corporation and Marathon Petroleum Corporation -- each positioned to deliver continued shareholder growth.... www.marathonoil.com www.marathonpetroleum.com An independent upstream company with international operations in Exploration and Production, Oil Sands Mining and Integrated Gas..., Marathon Oil Corporation (NYSE:MRO) is based in Houston, Texas. The fifth largest U.S. refiner with extensive marketing and transportation operations, Marathon Petroleum Corporation (NYSE: MPC) is based in Findlay, Ohio. ...