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.
Towards the end of the movie, when Sue uses Charlie's full name, Charles Postelwaite, Charlie calls Boss, "Bucket Mouth", the same thing Kevin Costner called his father in The Bodyguard (1992), when his father is sharing stories from Costner's childhood.
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.
Tig, Charley's dog, was played by a mixed-breed terrier named Chester. The dog Charley rescued from flood waters was actually played by two terrier mixes named Goldie and Boomer. They used two dogs so they wouldn't get too tired or cold from doing multiple takes.
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).