<P> In the 1800s, the principal refined product was kerosene for illuminating oil . The heaviest fraction was used as lubricating oil . A market developed for fuel oil as it was discovered that petroleum was superior to coal in powering the large engines of ships and railroad locomotives . </P> <P> The popularity of the automobile in the early 1900s created a mass market for gasoline, and a shortage soon developed of the lighter gasoline fractions of crude oil . The shortage was solved by the invention of the catalytic cracker, which broke long hydrocarbon chains into smaller molecules . </P> <P> Most large refineries are near navigable waterways, especially seaports or Great Lakes ports . The single largest concentration of refineries is along the Gulf Coast . Although there are refineries in 30 states, just three states dominate US refining: Texas (47 operating refineries), Louisiana (19), and California (18). As of January 2015, these three states contain 45% of all US refineries and 59% of all US refining capacity . </P> <P> The three largest - volume products of US refineries are gasoline, fuel oil (including diesel fuel and home heating oil), and aviation fuel, which together make up more than 84 percent of output . </P>

Where are most of the us oil refineries located