United States Park Police

The United States Park Police (USPP) functions as a full-service law enforcement agency with responsibilities and jurisdiction in those National Park Service areas primarily located in the Washington, D.C., San Francisco, and New York City areas and certain other government lands. United States Park Police officers have jurisdictional authority in the surrounding metropolitan areas of the three cities it primarily operates in, meaning they possess both state and federal authority.

Source: Wikipedia — United States Park Police (CC BY-SA 4.0)