Wikipedia:
In 2011, Time Magazine rated The Far Horizons as one of the top ten most historically misleading films, in part due to its casting of caucasian Donna Reed as Native American Sacagawea, and the creation of a romantic subplot between her character and William Clark despite the fact that Sacagawea's husband, French-Canadian trader Toussaint Charbonneau, was in real life also a member of the expedition.
In 1940's "The Westerner" it has Judge Roy Bean as someone who hangs people at whim, (Only 2 men were ever sentenced to hang and one escaped) behind the cattlemen, vs. farmers wars, (which never happened) and finally (SPOILER!) dying by Cooper's character's gunshot at the end of the film, which concludes in 1884. However, Bean died in his sleep in 1903 at the age of 78.
He wasn't a mean-spirited person, and always gave money to charities and supported the local schoolhouses.
Why ever expect Hollywood to be accurate? They are making movies for money, they not going to let historical accuracy get in the way.
..Joe