The sheriff is the boss of his county. Period. There is no higher authority in law. Not State police, not feds, nobody.
Sheriffs is it.
If he leaves his county he’s toast. But he is the king of his county. Feds do not rule his county without his permission.
That’s how he can keep them out.
If he’s fair, he’s reelected.
There is no such thing as one size fits all when pertaining to the Office of Sheriff in this country. All fifty states have different laws when it comes to defining the power and duties of the office of sheriff although some responsibilities tend to stay the same such as enforcing the state laws and county ordinances, maintaining the jail and state law civil process. Some states do not even have the office of the sheriff.
You basically implied that the sheriff has no power if he leaves his county. Well in some states such as mine the sheriff can make arrests state wide although he is limited in authoritative operational jurisdiction in other counties. That is a perfect example of there is no one size fits all pertaining the sheriff because all fifty states have all different verbiage in their statutes or maybe Constitution regarding the sheriff.
He is not sole king of the county because there are county legislators which in my state are regarded as County Commissioners.
Depending on the state, the sheriff may be the highest STATE LAW enforcement officer. That is the major key there. He is not the highest FEDERAL LAW enforcement officer. Federal agents are the highest federal law enforcement officers in 100 percent of every county in this great nation of ours. When it comes to FEDERAL LAW the sheriff is legally trumped by federal agents in his county and he can in no wise legally impede federal agents from faithfully performing their federal duties in his county. That is how the rule of law works. If the sheriff could rule his county as he or she sees fit then he could also interpret state laws as he or she sees fit. Fortunately, that is not the case. The notion that a sheriff is the king of his county is a wannabe basically myth that has no basis in the rule of law of this country.