England and Wales, two constituent countries of the United Kingdom, are policed by territorial police forces largely formed on a county basis.
Historically, Northern Ireland and Scotland, the other two constituent countries of the UK, have had county police, although both countries now have unified national police services.
[1] Territorial police forces that have a presence at a regional and county level in England and Wales are: In the United States, the powers, duties, and even existence of county police forces vary widely depending on the state, and even on the particular county (parish in Louisiana) within a state.
Many states also have a county sheriff's office, which is usually formed on a county basis and traditionally carries out duties related to the functioning of the courts and legal system, such as service of process, executing legal writs, and protection for the local courthouse and its judges.
Many state constitutions mandate that the position of sheriff be created, which leads many states to also give sheriffs the duties of a county police to avoid having overlapping departments with similar duties, leaving the sheriff as the exclusive law enforcement agency for a county.