Continuity mistake: A couple of times in the movie, the camera pans to John Wayne, and his hair is parted on the wrong side. (Reverse editing flaw).
Continuity mistake: When Josey was in the general store picking up supplies with the Indian man and women, Josey was handed a picture of Slim Fixin. If you watch carefully, he walks out with the picture. When you see Josey after he has walked out of the general store, he does not have the picture in his hand.