system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is the difference between police, sheriff and State Troopers?

I’m fairly new to living in the US and I see all three on the roads here. In the U.K. we only had police.
gpt
Police are town or city based, so they only have authority in their town/city.  Obviously since police are expensive not every little town has its own police, which takes us to the next thing.

Sheriffs. Sheriffs are at the county level. They are essentially the police force for the whole county and work across the county and all the towns in it. But they typically won’t spend much time in the cities or towns that have their own police forces because those places already have their own police, so you will more often see Sheriffs in more rural areas. But that does not mean they can’t come in the town/city.

Another thing about the sheriffs, the head of the sheriff’s department is an elected official. You vote for sheriff.

Then, the next step above that is State Troopers.

These are what you would think, state police, they have authority to work across the entire state.

Because of this, they will work most often on the interstates/large or busy highways between the cities, sometimes in the small rural towns, and will work on cases and coordinate with local police for things that span multiple towns/cities/counties.