Frederick Law Olmsted designed the grounds to visually transition the building from its urban surroundings into a more naturalistic park setting.
The Summerhouse was originally built to hide the entrance to a cavernous ventilation system for the Capitol building.
The grounds contain a specific collection of 'State Trees,' representing each U.S. state in designated areas of the park.
Many of the original trees planted in the 1870s were labeled with botanical information to serve as an educational outdoor museum.
The landscape architecture includes strategic embankments meant to make the Capitol appear elevated and more prominent from the western perspective.
Security barriers are designed as landscape elements, such as bollards disguised as benches or planters, to maintain aesthetic integrity.
The grounds were officially designated a historic site on the National Register of Historic Places in 1977.
The US Capitol Grounds comprise a 274-acre park designed by Frederick Law Olmsted, serving as the official landscape surrounding the United States Capitol building. The grounds feature a sophisticated arboretum with over 100 species of trees, many of which were original plantings from the 1870s. The landscape design incorporates stone terraces, retaining walls, and elaborate stairways intended to provide a stable, aesthetic base for the Capitol structure. It serves as a public space while maintaining strict security perimeters managed by the Architect of the Capitol. The grounds include the Summerhouse, a decorative brick structure built in the 1880s to provide shade and a source of cool water for visitors. The area is maintained as a living historic site and serves as a site for national ceremonial events.
The Senate Fountain area at the northwest corner provides the best unobstructed view of the building's dome.
Walk the perimeter of the western terrace for the most comprehensive view of the National Mall.
Check the official Architect of the Capitol website for current security access points, as entry protocols can change based on Congressional activity.
Bring a hat and sunscreen, as the vast majority of the walking paths through the open lawns have limited shade.
Do not attempt to enter through unauthorized doors or bypass security checkpoints, as these are monitored by federal law enforcement.
Maintain quiet, respectful behavior; avoid walking on restricted grass areas; do not climb on stone walls or balustrades.
