Law enforcement describes the agencies and employees responsible for enforcing laws, maintaining public order, and managing public safety. The primary duties of law enforcement include the investigation, apprehension, and detention of individuals suspected of criminal offenses. Some law enforcement agencies, particularly sheriffs' offices, also have a significant role in the detention of individuals convicted of criminal offenses.
BJS maintains several national data collections, covering federal, state, and local law enforcement agencies and special topics in law enforcement. Data are typically collected directly from law enforcement and related agencies, including crime laboratories, police departments, sheriffs' offices, and training academies. The most recent tool to access incident-based data on crimes recorded by law enforcement is the Law Enforcement Agency Reported Crime Analysis Tool (LEARCAT).
Most data collections are conducted every 2 to 4 years and report aggregate findings. From these collections, BJS publishes national estimates for personnel, equipment, operations, policies, budgets, and job functions across agencies.
One difference between a sheriff's office and police department is the jurisdiction that each type of agency covers. While both sheriffs' offices and police departments are law enforcement agencies, sheriffs' offices have countywide jurisdiction and police departments' authority is limited to specific cities, municipalities, towns, or villages. In addition, sheriffs' offices are generally empowered by the state to serve counties and independent cities, while police departments are established under municipal regulations. The head of a sheriff's office is a sheriff who is usually an elected official. The head of a police department is usually the chief, who is typically appointed by a government entity, such as mayor, city manager, or a commissioner.
In 2020, about 14% of full-time sworn officers employed by local police departments and sheriffs’ offices were female. As of 2020, 4% of local police chiefs and 1% of sheriffs were female. About 9% of intermediate supervisors (those between chiefs and sergeants or first-line supervisors) in local police departments and 10% in sheriffs’ offices were female. About 10% of first-line supervisors (sergeants) in local police departments and 12% in sheriffs’ offices were female.
According to the 2020 BJS Law Enforcement and Management Administrative Statistics (LEMAS) survey, departments serving 100,000 to 249,999 and 50,000 to 99,999 residents had the lowest average ratio (1.6 officers per 1,000 residents). Departments serving populations of 1 million or more had 3.0 officers per 1,000 residents.