Police Systems

The 17,500 police agencies at national, state, county, and municipal levels employ more than 800,000 people, sworn and unsworn. The agencies include

50 federal law enforcement agencies.
49 state police departments.
1,721 special police agencies (for example, transit police and school police).
3,086 sheriff's departments.
12,502 municipal police departments.

Federal police agencies

Federal law enforcement agencies are part of the executive branch of the national government. The major federal law enforcement agencies are

The Federal Bureau of Investigation (FBI): This Department of Justice (DOJ) agency investigates over 200 categories of federal crimes. The FBI emphasizes protecting the nation from terrorism, organized crime (which includes narcotics trafficking), white‐collar crimes, civil‐rights crimes, and violent crimes (such as bank robbery and kidnapping). It assists other federal, state, and local agencies through its crime statistics, crime lab, fingerprint files, and training academy. As organized crime has become a bigger business, the FBI has gained additional authority (including wiretapping authority) to combat it.
The Bureau of Alcohol, Tobacco, and Firearms (ATF): This Treasury Department agency investigates the criminal use of explosives and firearms. ATF also pursues outlaw motorcycle gangs who violate federal firearms, explosives, and drug trafficking laws.
The Drug Enforcement Administration (DEA): This DOJ agency is responsible for enforcing all federal drug‐control laws. Its agents investigate narcotics violators, seize drugs, and arrest drug traffickers.
The U.S. Marshals Service: Today's marshals provide security for all federal courts. They also protect members of the federal judiciary, except for the U.S. Supreme Court, which has its own police force. Marshals apprehend escaped federal prisoners, supervise those arrested, and operate the federal witness protection program (which gives new identities and security to some witnesses in federal trials).
The Secret Service: The Secret Service is responsible for apprehending anyone counterfeiting U.S. money and for protecting the president and other officials of the federal government.
The Immigration and Naturalization Service (INS): The INS polices the flow of immigrants into the United States. INS agents patrol the U.S. border to stop illegal immigrants from entering the country, and the agency deports aliens who break U.S. naturalization laws. In the 1990s, INS agents focused on the Mexican‐U.S. border, where large numbers of illegal immigrants and huge amounts of illicit drugs entered the United States. INS agents arrested hundreds of thousands of illegal immigrants each year, but the number making it safely into the United States still exceeded the number arrested.

Internationalization of law enforcement

Federal law enforcement agencies are increasingly stationing officers overseas. This trend is a response to the global scope of such crimes as drug trafficking, money laundering, and terrorism. By 1998, more than 1,500 American law enforcement officers were assigned to more than 50 countries.

State police

Every state except Hawaii has its own police force with statewide jurisdiction. The California Highway Patrol is the nation's largest state police force. Governors appoint the directors of state police or highway patrols. State police agencies do some or all of the following tasks:

Assist local law enforcement organizations in criminal investigations.
Maintain centralized crime records for the state.
Patrol the state's highways.
Operate a crime lab.
Train municipal and county police.

County police

Sheriffs are responsible for policing rural and unincorporated areas of the more than 3,000 counties in the United States. The position of county sheriff is an elected one. Many sheriffs perform law enforcement, court, and correctional duties. In many states, sheriffs operate the county jails and serve as officers of the county courts. The sheriff's office supplies bailiffs to provide security and management of defendants on trial. Sheriffs also transport prisoners to and from court and serve court papers. Sheriff's offices vary in size. The largest is the Los Angeles Sheriff's Department, with more than 11,000 full‐time employees. Of the more than 3,000 sheriff's departments in the United States, 19 departments have only one employee.

Municipal police

City police represent the largest number of agencies, employ most of the sworn officers, and shoulder the heaviest responsibility for dealing with violent crime. Mayors or city managers appoint the chiefs that head big‐city police departments. Departments vary in size and in the type of crime that faces them. The “Big Six” departments—New York, Los Angeles, Chicago, Houston, Philadelphia, and Detroit—deal with most serious violent crimes. The New York Police Department employs more than 36,000 full‐time officers. It confronts shootings, scandals, and corruption that make the national headlines. Most departments employ only a few people. In small departments, most calls to the police involve traffic violations and minor disturbances.