The United States police-rank model is generally quasi-military in structure. A uniform system of insignia based on that of the US Army and Marine Corps is used to help identify an officer's seniority.
Ranks
Although the large and varied number of federal, state, and local police and sheriff's departments have different ranks, a general model, from highest to lowest rank, would be:
Chief of police/police commissioner/superintendent/sheriff: The title police commissioner is used mainly by large metropolitan departments, while chief of police is associated with small and medium-sized municipalities; Both are typically appointed by a mayor or selected by the city council or commission. In some cities, "commissioner" is the member of the board of officials in charge of the department, while a "chief" is the top uniformed officer answering to the commissioner or commission. In very large departments, such as the New York City Police Department, there may be several non-police officer deputy and assistant commissioners, some of whom outrank the chief of department and others on par with the uniformed chief. There may be a chief of operations who is second in command to the top-ranking chief. In contrast, sheriffs in the United States are usually elected officials, one in each county, who head the sheriff's department.
Assistant chief of police/assistant commissioner/assistant superintendent: Only seen in some departments. In New York City, assistant chiefs head borough commands.
Inspector/commander: Sometimes have an insignia of a single star, analogous to brigadier generals, but in other areas wear a gold or silver eagle, similar to a colonel. "Inspector" is also used as a term for "detective" in the San Francisco Police Department but is two ranks above captain in the NYPD and the Philadelphia Police Department. In the NYPD, inspectors command divisions, which may be groups of precincts within a borough or specialized branches of the police service.
Colonel or Lieutenant Colonel: A majority of state police agencies use "colonel" or "Lieutenant Colonel" as their senior executive rank, often jointly with a civilian title such as "superintendent", "commissioner" or "director". Conversely, the colonel or Lieutenant Colonel rank is rarely employed by other agencies, though it is used by the Baltimore Police Department and other Maryland agencies as either an executive or commander-like rank. Colonels generally wear the gold or silver eagle of a colonel, or the oak leaf of a lieutenant colonel, from the U.S. armed forces. Many sheriffs also wear the eagle insignia, and use colonel as an official rank.
Major/deputy inspector: Sometimes have an insignia of a gold or silver oak leaf, similar to a major or lieutenant colonel. In the Baltimore Police Department and Atlanta Police Department, majors supervise police stations.
Captain: Two gold or silver bars. Often supervises a police station but can supervise another division or unit in smaller departments and only certain sections of a police station in larger departments. In the NYPD, captains are the normal commanders of precincts.
Lieutenant: A single gold or silver bar, who supervises two to three or more sergeants. Lieutenants can supervise an entire watch shift of a police station or detective squad in larger police departments and entire barracks in state police departments, and entire precincts in smaller police departments.
Sergeant: Three chevrons, a police officer who supervises an entire watch shift in smaller departments and areas of a precinct and individual detective squads in larger departments. Some agencies, such as the New Jersey State Police, use a para-militaristic range of sergeant ranks, such as staff sergeant and sergeant first class, in addition to the basic sergeant rank.
Detective/inspector/investigator: An investigatory specialist, usually working in plain clothes. This may be in several classes that correspond to higher supervisory and pay grades. In the NYPD, the detective rank is technically a designation: detectives do not actually outrank police officers although they are in charge of cases and are often senior in years of service, and so have a certain degree of authority beyond police officers in specific situations.
Officer/deputy/trooper/corporal: A regular officer/deputy wears no rank insignia, and there may be several pay grades. Corporals, who may be senior officers or acting watch commanders, wear two chevrons.
In a few departments, such as New York City and Philadelphia, officers from the rank of lieutenant and up wear a white shirt instead of the dark blue or black uniform shirt common to lower-ranked police officers. In Philadelphia the rank of sergeant and up wear white shirts. Senior police officers may wear fretting on their hat visors. Advancement from officer to captain is generally by appointment after successful completion of a series of examinations, and after the officer has sufficient time in grade. Grades above captain are generally by appointment of the chief/sheriff. In addition, there must be vacancies for a higher rank.
