Trivia: "Mad Dog" Tannen's actions after shooting Marty are a perfect homage by Thomas F Wilson to Lee Marvin in "The Man Who Shot Liberty Valance." He even gets the facial expressions, the mumbled and sarcastic thanks and the jaunty angle with which he holds the gun right.
Trivia: The wolf in the film was played by two different wolves. Neither knew how to howl, so a third wolf had to be brought in for the howling scene.
Trivia: John Chisum convinces Pat Garrett to accept a job as the new Lincoln County sheriff. James Coburn (Chisum) himself played Garrett in the Sam Peckinpah movie "Pat Garrett and Billy the Kid."
Trivia: The scene where Quigley triggers a booby trap by swinging his rifle from horseback, at full gallop, whilst holding it by the tip of the barrel with one hand, was only possible because an alternate aluminum barrel was created for that scene.