What is the difference between a Sheriff and a County Police officer?

Question

My question may be stupid, but in light of the recent bad PR of the Prince George's County Police Department, I'm wondering what the difference is between a County Police Department and the Sheriff's Department, if any. From what I've read, it seems that there is a difference, because (at least in Ohio) the Sheriff's Department would not have had jurisdiction to make that arrest, since it wasn't in a rural area without a police department. But, Prince George's County is much more populated than Southeastern Ohio, and is in an entirely different state.

Answer 1

The Sheriff is the primary law enforcement officer for the county. A deputy can make an arrest inside the city limits. They normally don't patrol the city as a matter of courtesy, not a matter of law.

The Sheriff also runs the jail, and is responsible for other civil matters such as paper service and evictions.

County police have the same authority as city police, but are employed by the county.

Answer 2

A sheriff's department is the law enforcement for the entire county.  They handle the unincorporated areas.  Those are areas that are not part of a city that has it's own police department.  They also run the jail.

In larger populated counties, like Prince George's or St. Louis County, the sheriff's department runs the jail and serves process (court orders).  While there is a county wide police department, that handles law enforcement issues county wide.