In 1926, Route 66, aka the Main Street of America, aka the Mother Road, was created to give wannabe actors and potential key grips traveling from Chicago to Los Angeles a standardized route to follow west, through Missouri, Kansas, Oklahoma, Texas, New Mexico, and Arizona. A side consequence of the route was providing mom-and-pop business opportunities for people in towns along said route, and it just so happened to run right through El Reno. According to the John T. Edge’s excellent book Hamburger & Fries: An American Story, at this time, a man named Ross Davis ran a restaurant called the Hamburger Inn in town along Route 66.
Because this was the Depression, hamburger meat was expensive, but onions were cheap. Davis started “smashing them into the meat with the back of his spatula. He called them Depression burgers and he’d smash a half-onion’s worth of shreds into a five-cent burger.” Apparently Davis’s spot was in a prime position -- at the intersection of Route 66 and Highway 81 -- and word of his creation spread quickly. Several other eating establishments in El Reno followed suit, and began making their own versions of the fried onion burger. A burger star was born.