Factual error: The town of El Dorado is located in Texas, as evidenced by the Texas county map on the wall in the County Sheriff's office. However, while on their journey to the town, Thornton and Mississippi shoot at Saugaro Cact, which is only found in the Sonoran Desert in what was then Arizona Territory.
Trivia: El Dorado is actually part of a remake trilogy by the same director, Howard Hawks. The first was 'Rio Bravo' (1959); 'El Dorado' was next in 1967; and the final variation was 'Rio Lobo' in 1970. El Dorado is the only humorous (and by many critics acclaimed as the best) version of the three.
Trivia: In the scene near the end of the film where Mississippi, JP, and Bull are attempting to sneak into the saloon through the back, Mississippi disables the guard at the back door by disguising himself as a Chinese person. In the original release of the film, he puts on the disguise, then squints his eyes and speaks in vaguely Asian-sounding gibberish. This was deemed insensitive and inappropriate, and when the film is shown on television, the scene cuts awkwardly to avoid the offensive expressions and dialog.Jason Hoffman
Sheriff J. P. Harrah: What the hell are you doin' here?
Cole: I'm lookin' at a tin star with a... drunk pinned on it.
Cole: Don't you know better than to follow a man that way?
Mississippi: Sorry... I didn't know there was another way.
Question: When Wayne exits Jason's ranch by guiding his horse backwards (a display of fine horsemanship and/or animal training, by the way), you may notice that he is holding his right hand exactly the same way as he does later in the movie when he has the bullet-against-the-spine problem and is temporarily paralyzed toward the end of the movie. Perhaps he did have a problem with his hand at that time, and the script was altered accordingly?