The preservation of the peace, protection of property and the arrest of offenders has been the goal of Baltimore residents since August 8, 1729, when the Legislature created Baltimore Towne.

The first attempt to organize a force to guard Baltimore occurred in 1784. Constables were appointed and given police powers to keep the peace.

The State Legislature on March 16, 1853, passed a bill, "to provide for the better security for the and property in the City of Baltimore." This statute provided that police officers should be armed and that a badge and commission be furnished each member.

In March of 1862, the military authorities who had taken control of the Department on June 27, 1861, turned over the Police Department to the authority of the state.

The Department then began a modernization program which continues today. In 1885, a call box system was established to provide a means of communications between officers on the street and "the station house."

The first patrol wagon went into service on October 25, 1885. In 1896, the Bertillon Bureau was established to take photographs and measurements of prisoners. A Harbor Patrol was established in 1885, the Traffic Division in 1908, and the Police Academy in 1913.

In 1920, the Board of Police Commissioners was established and General Charles D. Gaither was appointed as the first Police Commissioner.

The First radio communications system between patrol vehicles and a central dispatcher went into service on March 4, 1933. The Accident Investigation Unit was established on February 21, 1938, the Laboratory Division went into operation in June, 1950, and the Central Records Division was created on August 7, 1951.

Other innovations included the inception of the Marine Unit in 1860, and the Mounted Patrol in 1888. Since then, the deployment of the K-9 unit on March 1, 1956, the merger of the Park Police with the regular force on January 1, 1961, and the formation of the Helicopter Unit in 1970 have greatly expanded the services of the Police Department.

The Baltimore Police Department’s jurisdiction encompasses an area of 86.0 square miles: 78.3 sq. miles of land and 7.7 sq. miles on waterways. The present Headquarters Building of the Police Department was opened in 2021.