The law enforcement agency headed by a sheriff is commonly referred to as a "sheriff's office" not "sheriff's department."[3] According to the National Sheriffs' Association, an American sheriff's advocacy group, there were 3,081 sheriff's offices as of 2015.[4] These range in size from very small (one- or two-member) forces in sparsely populated rural areas to large, full-service law enforcement agencies, such as the Los Angeles County Sheriff's Department, which is the largest sheriff's office and the seventh largest law enforcement agency in the United States, with 16,400 members and 400 reserve deputies.
Of the 50 U.S. states, 48 have sheriffs. The two exceptions are Alaska, which does not have counties, and Connecticut, which has no county governments.
Sheriffs are elected to four-year terms in 42 states, two-year terms in Arkansas and New Hampshire, three-year terms in New Jersey, and six-year terms in Massachusetts.[5]
In many rural areas of the United States, particularly in the South, the sheriff has traditionally been viewed as one of a given county's most influential political office-holders.
Law enforcement officers working for an agency headed by a sheriff are typically titled sheriff's deputy, deputy sheriff, sheriff's police, or sheriff's officer, and are so-titled because they are deputized by the sheriff, sworn by the county clerk or county official and charged with performing all the duties prescribed to the sheriff by that state's law. In some states a sheriff may not be a sworn peace officer, but merely an elected civilian official lacking police powers who oversees the offices and its sworn peace officers. Law enforcement officers working for such offices may be subdivided, sometimes titled general deputy and special deputy.

In some areas of the country, such as in California's San Bernardino, Riverside, Orange, Sierra, Tulare and Ventura counties, the sheriff's office also has the responsibility of a coroner's office, and is charged with recovering deceased persons within their county and conducting autopsies. The official in charge of such sheriff's departments is typically titled sheriff-coroner or sheriff/coroner, and officers who perform this function for such departments are typically titled deputy sheriff-coroner or deputy coroner. The second-in-command of a sheriff's office is sometimes called an undersheriff or chief deputy, akin to the deputy chief of police position of a municipal police department. In some counties, the undersheriff is the warden of the county jail.

https://en.wikipedia.org/wiki/Sheriffs_in_the_United_States

W tym wypadku "officer" znaczy po prostu police officer czyli policjant, szeregowy członek policji. Tak samo jak trooper (w state police). Deputy też jest najniższym stopniem w policji szeryfa.

może tak ogólnie