Jack in the Box is an American fast-food restaurant founded by Robert O. Peterson in 1951 in San Diego, California, where it is still headquartered today. In total, the chain has 2,100 locations; primarily serving the West Coast of the United States. Most of the outlets are in California , followed by Texas Arizona , Washington, Nevada, and the bi-state St. Louis metropolitan area between Missouri and Illinois. The company also operates the Qdoba Mexican Grill chain.