It cracks me up that Hollywood can't find more comparable locations to film in then they do. The Ozarks do not look anything like the hills and forests out west. Kind of like True Grit's Fort Smith being filmed in Colorado even though the two don't even resemble each other. Come on Hollywood, as much as you spend making movies, film in comparable or even better the real locations.
shareThe locations of this film were chosen for logistical reasons as well as their looks. The locales of Billings and Bozeman, Montana were used as stand-ins for the Oklahoma Territories of 1893, and are well west of anything that might be considered 'Ozark'. For what it's worth, the Springfield Plateau and the Boston Mountains both run into eastern Oklahoma, albeit well short of the area known as the Cherokee Outlet. In all likelihood, the Outlet itself was probably ruled out by the production, as being simply too flat and featureless for filming. To be perfectly fair to the production, and the filmgoing public, not many people not living in this region would know any difference.
For what it's worth, almost every production depicting my region has gotten the trees wrong. This is very noticeable to me, but I wouldn't expect people outside of my region to know such a difference, much less care.