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State Police from WikiPedia:

State police are a type of sub-national territorial police force, particularly in Australia and the United States. Some other countries have analogous police forces, such as the provincial police in some Canadian provinces, while in other places, the same responsibilities are held by national police forces.

In the United States, state police are a police body unique to each U.S. state, having statewide authority to conduct law enforcement activities and criminal investigations. In general, they perform functions outside the jurisdiction of the county sheriff (Vermont being a notable exception), such as enforcing traffic laws on state highways and interstate expressways, overseeing the security of the state capitol complex, protecting the governor, training new officers for local police forces too small to operate an academy, providing technological and scientific support services, and helping to coordinate multi-jurisdictional task force activity in serious or complicated cases in those states that grant full police powers statewide.

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