Continuity mistake: Walter Burke leaves the balcony last, but has moved forward one place when the view switches to inside. Also, the closed door has partly opened. (00:05:50)
Factual error: Purdy is always wearing a bra with hook and eye in the back. These bras were not patented until 1911, much later than when the movie is depicted. (01:12:20)
Continuity mistake: When the Danby clan rides into town to get Joe out of jail, they ride up to the sheriff's office and get down from their horses. Pa Danby sends his other 2 sons inside to "get Joe." They come just three seconds later and all of the horses are gone. (01:22:10)
Suggested correction: The Danby Clan ties up the horses in front of the saloon, not the jail. Pa sends his two sons into the saloon to buy drinks while he goes across the street to get Joe. When the camera pulls back to show Pa Danby crossing the street, the horses are visible on the left side of the screen.
Revealing mistake: When McCullough is discussing Prudy's oddities with the matronly lady out front of the mayor's house, it is obvious that the lady is standing on a dirt-covered concrete sidewalk.
Continuity mistake: The Danbys ride in with 13 gunmen. Prudy kills two. Both are shown lying dead in the middle of the street. A few minutes later both dead Danbys are missing from the street and there are once again 13 live Danbys facing Joe stretched over the cannon.
Visible crew/equipment: During the closing scene, just as the deputy starts to walk towards the right of the screen, if you look between the two buildings, you can see the top of what appears to be a bus riding by.
Character mistake: When the mayor invites the new sheriff into his house, he calls out for his daughter, Prudy. But calls out "Trudy" several times instead. Later in the film he corrects himself.
