Less than a year before this movie was released, Robert Mitchum co-starred with Dean Martin in another western, 5 Card Stud (1968). Unsurprisingly, as a popular crooner, Martin sang the title song for that movie, as he had for several other films in which he appeared. In response, and despite the fact he was not known for his singing ability, Mitchum insisted on recording the title song of this film.
This film features the offspring of five Hollywood stars: Robert Walker Jr. is the son of Robert Walker and Jennifer Jones, Deana Martin is the daughter of Dean Martin, David Carradine is the son of John Carradine and Robert Mitchum's son, Christopher Mitchum, appears unbilled.
Robert Mitchum said he intended to retire from acting when this movie finished filming in August 1968, but the following year he agreed to star in Ryan's Daughter (1970).
Despite being top billed, Robert Mitchum does not turn up until 17 minutes into the film. Leading lady Angie Dickinson does not appear until around 43 minutes.