Plains Exploration & Production Company, an independent oil and gas company, primarily engages in acquiring, developing, exploring, and producing oil and gas properties in the United States. It owns oil and gas properties with principal operations in onshore California, offshore California, the Gulf Coast region, the Gulf of Mexico, and the Rocky Mountains. As of December 31, 2011, the company had estimated proved reserves of 410.9 million barrels of oil equivalent. Plains Exploration & Production Company was founded in 2002 and is headquartered in Houston, Texas.