Towards the end of film production, Kevin Costner and some friends made a surprise visit to a large pow wow gathering at Morley. Chief Ernest Wesley honored Costner for his work with the Lakota Indians and using the Sioux language in Dances with Wolves (1990).
During the filming of Open Range a young Native man, Romeo N. Ryder, hired to do extra security work, was stabbed to death in the nearby town site of Morley on Aug. 20, 2002. His brother 'Zach Ryder' worked on the Open Range set as a production trainee.
As revealed during his 2013 appearance on The Arsenio Hall Show, Sir Anthony Hopkins wrote fan letters to Kevin Costner and Robert Duvall after watching Open Range, complimenting them both on their performances in the movie.
Composer Michael Kamen replaced Basil Poledouris as the composer on the film, and contrary to general knowledge, Poledouris did not do a score, backing out after having seen the film temp tracked with music like his work from Starship Troopers (1997).
On the DVD release, a deleted scene called "Mose's Story". This is only a rough cut, and it reveals that in some scenes, the beautiful sky and clouds were chroma keyed into the shot. In this rough edit, no attempt has been made to track the sky with the camera moves, and the effect is obvious.