From Howard Stansbury's discovery of "petroliem" along the northern shore of the Great Salt Lake in 1851 to the opening of the giant Overthrust Belt fields in Summit County in the late 1970s, the history of Utah's oil industry has been one of slow and intermittent development. The first companies to drill within the state were generally small and poorly financed, and the majority of wells they drilled did not even reach a depth of 1,000 feet. None produced the 300 barrels of oil a day that Equity's first well initially yielded. Only gradually did the large petroleum companies enter Utah, and they did not succeed in discovering commercial quantities of oil until after 1948. Most of their development has occurred in the eastern third of Utah, from the Uinta Mountains to the San Juan River.
In the 140 years since Stansbury's first discovery, nearly one hundred sixty fields have been explored, and approximately 900,000,000 barrels of oil have been produced in Utah (Texas yielded almost that much petroleum in 1947). Utah's number of productive wells increased from 225 in 1957 to 875 in 1968 and 1,300 in 1978. While the state's contribution to the amount of oil produced in the United States has remained relatively minor, the petroleum industry has become one of Utah's significant commercial enterprises.