When the evil Arliss Loveless is announcing his plan for dividing the United States, he mentions several states that were not yet states in 1869, including Arizona and New Mexico which became states around 1912.
These kinds of mistakes always pisses me off! When they use millions upon millions of dollars making a movie like this, mistakes like this is downright criminal. If "changing history" is necessary to the plot, ok, but it is not so here. It would have taken them, what?, 10 minutes of research...