Factual error: When they show the capital building in Washington DC it is still under construction, but it was actually finished in 1864 - 5 years before the movie's set.
Factual error: In any number of scenes in this movie characters are seen wearing celluloid badges in support of statehood for Wyoming. This movie is set in the year 1890 and the process of making celluloid badges wasn't developed until 1896.