Minn. Stat. sec. 624.714
Subd. 2. Scope. A permit to carry a pistol ... is a state permit and is effective throughout the state.
Subd. 23. Exclusivity. No sheriff, police chief, governmental unit, government official, government employee, or other person or body acting under color of law or governmental authority may change, modify, or supplement these criteria or procedures, or limit the exercise of a permit to carry.
The MN State fair unfortunately ignores this and proceeds to ignore the law.
Anyone correct if I'm wrong on any of this but I believe they do have the "ban signs" up every year.