The United States Capitol Police (USCP) is a federal law enforcement agency in the United States with nationwide jurisdiction charged with protecting the United States Congress within the District of Columbia and throughout the United States and its territories. It answers to the Capitol Police Board and is the only full-service federal law enforcement agency appointed by the legislative branch of the federal government of the United States.
The United States Capitol Police has the primary responsibility for protecting life and property, preventing, detecting, and investigating criminal acts, and enforcing traffic regulations throughout a complex of congressional buildings, parks, and thoroughfares. The Capitol Police has primary jurisdiction within buildings and grounds of the United States Capitol Complex. It also has concurrent jurisdiction with other law enforcement agencies, including the United States Park Police and the Metropolitan Police Department of the District of Columbia, in an area of approximately 200 blocks around the complex. Officers also have jurisdiction throughout the District of Columbia to take enforcement action when they observe or are made aware of crimes of violence while on official duties.
Additionally, they are charged with the protection of members of Congress, officers of Congress, and their families throughout the entire United States, its territories and possessions, and the District of Columbia. While performing protective functions, the Capitol Police have jurisdiction throughout the entire United States. It is informally considered as the sister agency of the United States Secret Service, which itself is responsible for the protection of the United States President and their Cabinet.