Although highly fictionalized, this is the story of a real Mountain Man, whose nom-de-plume was "Liver Eating" Johnson--so-called because he habitually ate the livers of the Crow Indians he killed in his vendetta against them.
I was surprised by the casting of Redford as Johnson--almost as ridiculous as casting Alan Ladd as Jim Bowie in the old movie, The Iron Mistress, and for the same reason: Alan Ladd was a shrimp. Bowie was well over six feet tall in his stocking feet; some say six foot five.
But Redford came through with flying colors, although the screen writers left out many fascinating details of Johnson's (originally Johnston) exciting life. The movie was filmed in the wilds of Utah, and filming began before the script was finished. Weather was a huge problem, as well, and the studio never spent enough money and effort promoting it, but still it did very well at the box-office, eventually.
Driving through Montana and northern Wyoming several years ago, we passed Crazy Woman Mountain, which I think was probably named after Mrs. Morgan (in the story), whose family was killed by Crows (as was Johnson's); hence his killing spree.
This is a movie well worth seeing. It is not only entertaining, but the Utah scenery is delightful, and there is even a little insight into the actual hardships of the real Mountain Men of the Rockies, Sierras, Cascades and Blue Mountains of the West.
Joseph (Joe) Pierre