The United States Capitol Grounds is a jurisdiction of the Architect of the Capitol.  The grounds of the U.S. Capitol were designed by Frederick Law Olmsted (1822-1903), who planned the expansion and landscaping of the area that was performed from 1874 to 1892.  In describing his plan for the Capitol Grounds, Olmsted noted that "the ground is in design part of the U.S. Capitol, but in all respects subsidiary to the central structure." Therefore, he was careful not to group trees or other landscape features in any way that would distract the viewer from the U.S. Capitol Building.

There are currently about 890 trees surrounding the immediate Capitol Building on Capitol Square and more than 4,300 trees throughout the entire 274-acre Capitol Grounds.  Sixty-five of the trees planted during Olmsted's original design remain today.  Many of the trees on the Capitol Grounds have historic or memorial associations. A number commemorate members of Congress and other notable citizens, national organizations and special events. In addition, more than 30 states have made symbolic gifts of their state trees to the Capitol Grounds.  Further information may be found at this link.