5 Largest Refineries in the US

2.  Marathon Petroleum Corp, Louisiana

Barrels per Calender Day: 596,000

Company: Marathon Petroleum Co LP

Site: Garyville

The Garyville Refinery, owned by Marathon Petroleum Corporation, is America’s second-largest oil refinery, with a capacity of 596,000 barrels per day. Nestled in Garyville, Louisiana, it spans 3,500 acres along the Mississippi River. Construction initiated in 1973, culminating in completion by 1976, later expanded in 2009 through the $3.9 billion Garyville Major Expansion Project. Their operations include crude distillation, hydrocracking, catalytic cracking, and more, primarily refining heavy sour crude into gasoline, diesel, and other products. With 900 employees and 600 contract workers, it plays a key role in the region’s energy landscape, capitalizing on varied transportation modes for feedstock supply.