The sheriff is an officer of the court, and his primary purpose and function is to serve and execute the various legal processes and mandates issued not only by and for the several courts of the state and its subdivisions, but also for the legal community and the general public. Although the authority of the sheriff varies from state to state, a sheriff or his deputies has the power to make arrests within his or her own jurisdiction. Some states extend this authority to adjacent counties or to the entire state. Many sheriff's offices also perform other functions such as traffic control and enforcement, accident investigations, and maintenance and transportation of prisoners. Larger departments may perform criminal investigations or engage in other specialized law enforcement activities. As the trends of sheriff's law enforcement duties becoming more extensive and complex continue, new career opportunities for people with specialized skills are opening up in sheriff's offices around the country. Among the specialties now in demand are underwater diving, piloting, boating, skiing, radar technology, communications, computer technology, accounting, emergency medicine, and foreign languages. Sheriff's offices may coexist with other county level law enforcement agencies such as county police, county park police. Sheriffs in the United States generally fall into three broad categories; Restricted service, Limited service, Full service. There are two federal equivalents of the sheriff; the first is the United States Marshals Service, an agency of the Department of Justice.
In the Restricted service category provide basic court related services such as keeping the county jail, transporting prisoners, providing courthouse security and other duties with regard to service of process and summonses that are issued by county and state courts. The sheriff also often conducts public auction sales of real property in foreclosure in many jurisdictions, and is often also empowered to conduct seizures of chattel property to satisfy a judgment. In other jurisdictions, these civil process duties are performed by other officers, such as a marshal or constable. Examples are the Philadelphia Sheriff's Office in Pennsylvania and the New York City Sheriff's Office (a division of the NYC Department of Finance). In the limited service of the sheriffs department along with the above, perform some type of traditional law-enforcement function such as investigations and patrol. This may be limited to security police duties on county properties to the performance of these duties in unincorporated areas of the county, and some incorporated areas by contract. One example is the San Francisco Sheriff's Department in California. Full service is the most common type, provide all traditional law-enforcement functions, including countywide patrol and investigations irrespective of municipal boundaries. There are 94 United States Marshals, one for each federal judicial district. The U.S. Marshal and his or her Deputy Marshals are responsible for the transport of prisoners and security for the United States district courts, and also issue and enforce certain civil process.
In California, a sheriff is an elected official and the chief law enforcement officer in any given county. The sheriff's department of each county polices unincorporated areas. As such, the sheriff and his or her deputies in rural areas and unincorporated municipalities are equivalent to police officers in the cities. The sheriff's department may also provide policing services to incorporated cities by contract Sheriff's departments in California are also responsible for enforcing criminal law on Native American tribal land. The Sheriff is charged with the responsibility of maintaining the public peace and protecting the lives and property of all citizens. The duties of the Sheriff have increased as administrative procedures, court