Filming for this picture took place in Nogales, Arizona exactly 30 years after William Holden had shot his first western, Arizona (1940), also in Nogales. That Columbia Pictures release became one of the most successful films of its year, and strengthened the young actor's career.
One of the rare instances where Blake Edwards collaborated with another composer instead of his regular musical associate, Henry Mancini, who was working on another movie. In this case he used Jerry Goldsmith.
Blake Edwards originally shot this film as a three-hour epic. But when the picture received negative feedback during previews, MGM cut about 40 minutes out of the film without his knowledge. They also altered the ending. Edwards had considered this his best film, but after the cuts he disowned it.
The scene in which Ross and Frank tamed a mustang was mostly done by the actors rather than stunt men. Blake Edwards wanted the action to be as believable as possible, so he had them train as horse wranglers in Iceland for five weeks before filming. At one point, a dark patch can be seen where William Holden later admitted to having pissed himself 'just a little'.
The original poster for the initial release of the picture had William Holden and Ryan O'Neal riding on the same horse with O'Neal's arms around Holden - as can be seen in the Photos section here. However, this generated speculation of a homosexual relationship between the two characters, so the studio withdrew that poster and replaced it with the one showing them wielding and firing revolvers.