The out-of-control Blue Cut Fire destroyed the landmark Summit Inn Restaurant in Oak Hills on Tuesday afternoon.
Video showed the flames consuming the well-known restaurant, located at the crest of the 15 Freeway.
For 60 years, the roadside diner has been a familiar sight for those traveling along historic Route 66, according to the restaurant's website.
"Numerous famous faces have visited us in the past, including Elvis Presley, Clint Eastwood, and Pierce Brosnan," the website stated.
Earlier in the day, the restaurant posted photos on its Facebook page as the fire approached.