HollyFrontier Corporation operates as an independent petroleum refiner in the United States. The company operates through two segments, Refining and HEP. It primarily produces high-value refined products, such as gasoline, diesel fuel, jet fuel, specialty lubricant products, and specialty and modified asphalt. The company offers its products to other refiners, convenience store chains, independent marketers, retailers, truck stop chains, wholesalers, railroads, governmental entities, paving contractors or manufacturers, and commercial and specialty markets, as well as for commercial airline use. It owns and operates five refineries with a combined crude oil processing capacity of approximately 457,000 barrels per day in El Dorado, Kansas; Tulsa, Oklahoma; Artesia, New Mexico; Cheyenne, Wyoming; Woods Cross, Utah; and vacuum distillation and other facilities in Lovington, New Mexico, as well as owns and operates asphalt terminals in Arizona, New Mexico, and Oklahoma. The company's refineries serve markets in the Mid-Continent, Southwest, and Rocky Mountain regions of the United States. The company was formerly known as Holly Corporation and changed its name to HollyFrontier Corporation as a result of its merger with Frontier Oil Corporation in July 2011. HollyFrontier Corporation was founded in 1947 and is based in Dallas, Texas.