Exterior shots account for 90% of the film, which was marked by photographic realism.
Robert Francis was originally cast as Steve Miller but died in a plane crash two weeks before he was set to begin filming on location in Colorado. He was replaced by Don Dubbins.
Director of Photography Robert Surtees delayed filming for four days to wait for the right weather conditions in order to create an ominous mood at dusk during an overcast day for the hanging scene.
Spencer Tracy was cast as Jeremy Rodock but was replaced by James Cagney, after he complained and procrastinated about working on that location because of the altitude of the Rockies. This essentially resulted in him being fired from MGM, his home studio since 1935.