During the nineteenth century, unofficial bodyguards and watchmen protected the president. In 1842, an auxiliary guard was implemented, which slowly grew throughout the century to include doorkeepers who managed public access to the White House and were expected to neutralize any potential threats.

The U.S. Secret Service was originally established by the Department of the Treasury in 1865 to prevent counterfeiting. They later assumed full-time responsibility for protecting the president during the Theodore Roosevelt administration, prompted by the assassination of his predecessor, William McKinley. Since the Roosevelt administration, the force has grown exponentially, been reorganized and restructured, and in 2002 it was moved out of the Department of the Treasury and into the Department of Homeland Security.

Learn more about the history of the Secret Service here.