In the film brothers Frank, Sim, and John are lynched. In reality John was not hanged by the vigilantes but had been imprisoned and lived until 1895. Bill was the third brother hanged although in the film he is killed in a bungled bank robbery early in the film.
Although the film shows two of the identified vigilantes were imprisoned for the crime, in reality not one of the 65 man lynch mob was ever identified or punished.
Although the film is set in the Midwestern state of Indiana, the opening sequence shows a desert landscape and the kind of towering buttes found in the Southwest--e.g., Utah and Arizona--and not on the flat
prairies of Indiana. Edit: Southern Indiana, where the film takes place is not prairie, but rolling hills and except for desert or mountains, the film locations looked essentially correct.
Set in Indiana in 1866, the opening sequences reveal telephone poles and telephone lines in the background. Also, the U.S. and California State flag are shown on a flagpole in the background. (The film was shot in California)
Set in 1866. A newspaper headline states that a man was cremated in a barn fire. Although cremations had existed for centuries, they were quite rare in the Americas. The first crematorium on this continent didn't open until 1876. It seems unlikely that the term would have been common enough a decade earlier to have been used in a frontier paper.
In the second train robbery, the sound of the steam locomotive is on a 2-3 second loop and was added in post production.