In Back to the Future, when Michael J. Fox first enters his hometown, circa 1955, this film is playing at the local cinema.
The film was originally supposed to have a theme song. Composer Louis Forbes wrote a melody and asked noted Western songwriter Bob Nolan to contribute lyrics. The song, 'Montana,' was not used in the film, but Nolan's former group the Sons of the Pioneers recorded it.
The role of Farrell was originally offered to Robert Mitchum, who turned it down because he didn't like the script. It was then offered to Ronald Reagan, who took it.