The New York City Police Department (NYPD), officially the City of New York Police Department, is the largest municipal police force in the United States. Established in 1845, the agency has primary responsibilities in law enforcement and investigation within the five boroughs of New York City. The NYPD is one of the oldest police departments established in the U.S., tracing its roots back to the nineteenth century.
The Department is administered and governed by the Police Commissioner, who is appointed by the Mayor. Technically, the commissioner serves a five-year term; as a practical matter, the commissioner serves at the Mayor's pleasure. The commissioner in turn appoints numerous deputy commissioners. The commissioner and his subordinate deputies are civilians under an oath of office and are not uniformed members of the force who are sworn officers of the law.
While the NYPD has 77 precincts, they are not sequential in their numbering. This was done to allow possible future expansion although reportedly most that have been added later have been merged with nearby ones. When it was created, the numbering system started in Manhattan at one, The Bronx at 40, Brooklyn at 60, Queens at 100, and Staten Island at 120. Most of the precincts used in TV series' are fictional, although the numbers typically are within the range for the area the show takes place.