Factual error: We learn that the previous sheriff, Charlie Wade, took revenge on anyone who smuggled illegal immigrants across the border in the late 1950s - we are shown the smuggling, as Eladio Cruz hides a group of Mexican men in a watermelon truck to take them across the border. However, in the 1950s, the border was not fortified the way it is now - the smuggling shown would simply not have been necessary.
Continuity mistake: When the Colonel appears in full dress green uniform in his estranged father's bar, the colonel's shoulder insignia (eagles) are on upside down.
Factual error: In the scene where the colonel is counseling the private for her failed drug test, the rank insignia on her hat is turned up-side down. This mistake, along with the colonel's rank also being up-side down, leads me to wonder if it was done deliberately.
Factual error: The private's rank on her hat is upside down.