Michael Pate who plays the Indian chief was also in real life an expert in Old West Military procedure. He told later that the Indian attack in the movie was not realistic at all, because Indians were experts in guerrilla warfare and would never have been trapped in an arroyo by the U.S. Army.
It was filmed near Camargo in the Mexico desert in temperatures reaching 126 degrees.
Geraldine Page's allergy to the sun meant that she was only able to withstand the heat from the sun for a few minutes at a time.
Pal, the dog that played Sam, was the original screen Lassie. In this movie, he is supposed to be vicious and ill-tempered, but the temperatures during filming were so hot, he simply panted instead of snarling when on-camera. In order to overcome this, he was kept in a special air-conditioned crate while on-set, and was only brought out for his shots.
John Wayne was originally to be only the producer for his Batjac company, and wanted Glenn Ford for the title role. However, Ford had such an unpleasant working experience with Director John Farrow on their previous collaboration, I saccheggiatori del sole (1953), that he turned down the offer. Wayne then took on the role himself.