If you were cited and arrested by a park ranger the resulting possible penalty for a conviction could vary if your were arrested on federal land or state land. Federal law has different penalties for a driving under the influence than state law.A park ranger is essentially law enforcement for the given park (federal or state land) and is empowered by statute to arrest and cite individuals for criminal offenses.In essence there is no distinction as to the legality of an arrest or citation by a park ranger of a police officer (or sheriff) of a given township. I recommend that you do consult with a criminal defense attorney over the charge or charges against you.Good question.