It depends on how each states laws are as to how law enforcement acts in the different 50 states in my state of ND the NDHP have jurisdiction everywhere and can go anywhere they wish but mainly stay to the US and ND highway system and patrol all state property. The Sheriff under the ND century code is the top law enforcement officer in the county after the state and he is charged with patrol all county roads and highways and providing law enforcement to municipal areas that have no form of local enforcement.