Historically, a sheriff was a legal official with responsibility for a "shire" or county. In modern times, the specific combination of legal, political and ceremonial duties of a sheriff varies greatly from country to country.
The word sheriff is a contraction of the term "shire reeve". The term, from the Old English scīrgerefa, designated a royal official responsible for keeping the peace (a "reeve") throughout a shire or county on behalf of the king. The term was preserved in England notwithstanding the Norman Conquest. From the Anglo-Saxon kingdoms, the term spread to several other regions, at an early point to Scotland, latterly to Ireland and to the United States.
In British English, the political or legal office of a sheriff, term of office of a sheriff, or jurisdiction of a sheriff, is called a shrievalty in England and Wales, and a sheriffdom in Scotland.
The Arabic term sharif ("noble"), sometimes rendered sherif, bears no historical or etymological connection.
A sheriff's office exists in most Australian states and territories, with various duties.
Most provinces and territories in Canada operate a sheriffs service. Sheriffs are primarily concerned with services such as courtroom security, post-arrest prisoner transfer, serving legal processes and executing civil judgements. Sheriffs are defined under section 2 of the Criminal Code as "peace officers". Sheriff's duties in Ontario deal only with serving legal processes and executing civil judgments. They do not perform court security-related duties. Court security functions are handled by the jurisdictional police (municipal police or the Ontario Provincial Police) in which the courthouse is located. In other parts of Canada, where sheriff's services do not exist, the Royal Canadian Mounted Police perform these duties. Quebec has a two-tiered court security system where armed provincial special constables perform court security and the provincial correctional officers perform prisoner escort/transport duties.
In 2006, the Province of Alberta expanded the duties of the Alberta Sheriffs Branch (the successor to the former Courts and Prisoner Security agency) to include traffic enforcement, protective security and some investigation functions (SISU and SCAN). As of June 2008, the Alberta Sheriffs Branch traffic division includes 105 traffic sheriffs who are assigned to one of seven regions in the province. Sheriffs also assist various police services in Alberta with prisoner management.