Non cop here so bear with me. What is the difference between a State trooper, State police and a highway patrol? As I understand it none are city or county level(City PD, or sheriff deputy). Are the names significant in different duties/ jurisdictional areas? Is this a east coast vs west coast thing?

Just whatever the specific state came up with when writing the statutes.

Thanks.

Probably the above, but some states have multiple agencies at  state level.

For example, University of California PD are a state agency.

In South Carolina you have several state level agencies where the officers went through the state law enforcement academy and I have been told all have the same level of authority.  This includes Public Safety Officers, State Troopers, Capitol Security, DNR Officers, etc.  Well...actually a State Trooper told me that the "Public Safety Officers" are the ones who graduate at the bottom of the class...

Missouri refers to it's state police agency as the "Missouri State Highway Patrol".

But rest assured they will push your shit in out in the middle of the woods just as quickly as they will roadside if need be!

All depends on the state. 9/10 they patrol the interstate and major highways in any given state. In my area (rural where the local cops don't have the personnel to be in 24/7) state troopers patrol the streets of the small towns and assist the local officer/deputies

As a rule highway patrol implies just road cops.  State police tends to imply a full service agency with detectives, investigators and the like.   But as others have said it really boils down to what the statutes say and they're not very consistent.  

In Iowa we have the State Patrol, which is uniformed road cops, the Division of Criminal Investigation (basically a state FBI), there's a separate agency for the casinos, and I think we still have a drug enforcement agency.  The DOT weight cops were merged with the State Patrol a few years ago but still have a separate identity and bargaining unit.  The State Patrol also does capital and executive security.

State Police means they have jurisdiction in the entire state.
State Patrol may or may not have limits on jurisdiction.

Arizona Highway Patrol has jurisdiction in the entire State, but they let locals handle the non traffic stuff, because they couldn't figure out if there was a domestic if the bloodied participants were standing in front of them.

I don't know if it has changed, but back in the 90's when I was a Deputy in Ohio, the Ohio Highway Patrol had no jurisdiction outside the fences of the Highway (the highway includes berms, sidewalks, and of course, the travel way, that vehicles travel on).

Many of our guys were surprised to discover that back then (again, I don't know if it has changed), OHP or OSP, depending on who you ask, did not even have the authority to carry off duty.
One of their guys took a plea in a domestic case to low class misdemeanor unlawful carrying a firearm, which saved his job.

Jay

I always ask the state police why they’re not called commonwealth police. Haven’t gotten a good answer yet.

Because it's not The United Commonwealths of America?

It depends on your state.  "Highway Patrol" could mean they are out patrolling the highway, but just be a division of the State Police.  In other states, State Police sometimes refers to the police who are responsible for guarding the State Capitol, monuments, state parks, etc.  In some, they are combined and do it all.  State Trooper is the title of the officer, like Police Officer, Sheriff's Deputy, etc.

Hope I didn't muddy the water too much.

Still haven’t gotten a good answer.

I think most with the highway patrol name (for a full-service state agency) were just early adopters of that name when highways were new, way before the interstate system.

State police was probably more popular by the mid-1930s.

My state has a Highway Patrol and not a State Police.  They primarily work traffic enforcement and accident investigation on the state and county highways and roadways outside of incorporated areas.

The Highway Patrol does not perform traditional law enforcement roles in the unincorporated areas as this is performed by the elected sheriff in each county (Duval and Miami are kind of exceptions to this of the 67 counties in Florida).

I would argue a good rule of thumb is State Police often provide traditional law enforcement services in areas outside of cities in most states.  Highway patrol will be more focused or statutorily restricted to enforces the laws as it relates to roadways in the state.

Minnesota State Patrol is statewide jurisdiction, but they’re oriented towards all state roadways.  They don’t enforce fish and game (that’s the MN DNR), and they don’t patrol state unincorporated areas.  Any part of the state that is unincorporated that doesn’t have a local agency is the responsibility of the county sheriff’s office.  The State does not have responsibility for that, nor the jurisdiction.  Nor the training, because normal police calls scare them.  But MN State Patrol exist for traffic enforcement, protection of the Governor and protection of state property in times of civil unrest/riot.  Because they have statewide jurisdiction, they can deploy anywhere without a mutual aid request, and they’re not subject to home agency restrictions.  This was a huge benefit for them during the Minneapolis riots this summer where MSP did their own thing and didn’t answer to the command staff admin cucks running Minneapolis into the ground.

Different nomenclature is the same as different uniforms...agency preference and history.

I have wondered that as well.

VA State Police has statewide jurisdiction, an investigative division, and will handle calls in the more rural counties but is mostly a highway patrol.