Magnificent locations, a pleasant adventure: "Yellowstone Kelly" is a typical nice western movie of the 1950s and, in my personal opinion, it is a relevant instance of a better way of making cinema (better than the current one, I mean).
The movie has merits and defects. Among the merits (apart the already quoted beauty of the photography): the fast-pace of the narration; a number of well-elaborated action scenes; the presence of Andra Martin as the Arapaho girl Wahleeah. In fact, beautiful Martin manages to create, with few but skillful touches, a soft erotic atmosphere rather unusual in western movies of that epoch. However, it should be noted that her (splendid) blue eyes are a relevant clumsiness of the movie. Clint Walker, in the role of the trapper Yellowstone Kelly, is a nice guy, though certainly not a great actor. As always in mature 1950's westerns, the war between whites and Indians is provoked by either hot-heads or rogues, in the present case a stupid ambitious cavalry officer: this remark is just intended to contradict the false common-place that in those years Indians were always represented as blood-thirsty savage assassins.
The story is placed around the Wyoming-Montana border: however the final part was evidently filmed in the wonderful area of Sedona, Arizona. I'm not able to decide whether this could be considered a defect of the movie: probably not. The worst flaw in the film is the fact that all Sioux perfectly understand and speak English (?). There are several other inaccuracies. For instance: I may be wrong, but I bet that the Blue Soldiers had never been equipped with Winchester carabines.
I saw "Yellowstone Kelly" at the theatre, when I was a kid: the pleasant impressions I retained have been confirmed by my recent new view at the TV. I recommend this movie, especially to people nostalgic of good old western flicks.