Petroleum in the United States has been a major industry since shortly after the oil discovery in the Oil Creek area of Titusville, Pennsylvania in 1859. The petroleum industry includes exploration for, production, processing (refining), transportation, and marketing of natural gas and petroleum products. As of 2008, the U.S. was the world 's third - largest oil producer (after Saudi Arabia and Russia), producing 8.5 million barrels of oil and natural gas liquids per day. The leading oil - producing area in the United States in 2014 was Texas (3.17 million barrels (504,000 m) per day), followed by the federal zone of the Gulf of Mexico (1.40 million barrels (223,000 m) per day), followed by North Dakota (1.09 million barrels (173,000 m) per day) and California (0.50 million barrels (79,000 m) per day).
where is the most oil produced in the us
Texas