The United States Park Police enjoys a long and colorful history. Formerly known as park watchmen, they have been continuously on duty in the older parks of the District of Columbia from the early days of the city's inception. Control of the Force has passed through a long succession of Federal entities, predating both the Department of the Interior (est. 1849) and the the National Park Service (est. 1916). From modest beginnings, the Force has grown to become a highly regarded law enforcement agency.
The history of the United States Park Police is intrinsically linked with the formative years of our Nation's Capital. Following a mandate from Congress, President Washington appointed the first board of trustees, called "Commissioners," in 1791. These three commissioners implemented plans for the development of a new district at the confluence of the Eastern Branch (Anacostia) and the Potomac River that would become the seat of government for the United States. In addition to providing suitable buildings for Congress, the president, and other departments within the government, they were responsible for the protection and care of all public property. To this end, watchmen were hired to safeguard the newly acquired public buildings and grounds. Inasmuch as the National Park Service is legal successor to the original commissioners' office with respect to national capital parks function, the United States Park Police can likewise trace their functional lineage to the early watchmen.
In 1802, the office of the Federal Commissioners was abolished and their duties conferred upon a Superintendent of Public Buildings and Public Grounds. In 1816, the responsibilities of the superintendent were transferred to one commissioner who reported directly to the president.
There was initially one watchman on duty at the Executive Mansion, later to become known as the White House, and one at the Capitol Building. In 1827, the number of watchmen at the Capitol was expanded to 4. By an Act of Congress l year later, the watchmen at the U.S. Capitol became separate and distinct from those under the direction of the Commissioner of Public Buildings, reporting instead to the presiding officers of the House and Senate. The Interior Department was created in 1849 and assumed control over the park system of the Nation's Capital until 1867, when this responsibility was passed to the Chief Engineer of the United States Army. During the military's tenure, oversight of day-to-day operations was delegated to an active duty officer, normally a major or colonel. His responsibilities as the officer in charge of Public Buildings and Grounds included supervision of the park watchmen. The Force at that time was comprised of 2 watchmen assigned to the Executive Mansion, 5 at the Smithsonian Grounds (the Smithsonian “castle" building having been constructed between 1847 and 1857), and 1 at Franklin Square.