Several reasons have been put forward for the film being in black and white. John Ford once claimed it added to the tension, but others involved with the production said Paramount was cutting costs, which was why the film was shot on sound stages at the studio. Without the budget restraints, Ford would have been in Monument Valley using Technicolor stock. It has also been suggested that since both John Wayne and James Stewart were playing characters 30 years younger than they're actual age (Wayne was 54 when the movie was filmed in the autumn of 1961 and Stewart was 53), the movie needed to be in black and white because they would never have got away with it in color. The age difference was particularly noticeable in Stewart's case, since he was playing a young lawyer who had only just graduated from law school and had moved west without even practicing law back east.
When Dutton Peabody stumbles back drunk to his newspaper office, he partially recites the Saint Crispin's Day speech from William Shakespeare's "Henry V". The speech, given just before Henry V's army defeats a superior French force, foreshadows the upcoming gun battle between Ransom Stoddard and gunslinger Liberty Valance.
Valance addresses several characters as "dude." From the 1870s to 1960s, this was a pejorative term with the approximate meaning of "overdressed city slicker," usually applied to city dwellers visiting rural areas. In the 1960s, surfer culture adapted the term to mean "friend" or "companion."
Tom Doniphon (John Wayne) refers to Valance as "... the toughest man south of the Picketwire," then adds, "next to me!" The Picketwire is not a wire fence dividing line; it was slang for the Purgatoire River, which flows into the Arkansas.
In promotional posters for the film, James Stewart appears to be billed first; however, in the film itself, John Wayne's screen card appears first, followed by Stewart's. In addition the studio ordered all theater managers to place Wayne's name before Stewart's on their marquees.
In the scene where Stoddard is carried into the "Peter's Place" kitchen wounded, Nora (Jeanette Nolan) gives him a cup of coffee laced with what she describes as "Akvavit, Swedish brandy" - the bottle is, in fact, a quite recognizable Akvavit bottle. The drink is found in all of Scandinavia but is largely considered to stem from Denmark.