National Expansion Memorial Cultural Landscape (U.S. National Park Service)

Tree-lined allee leading towards one leg of the Gateway Arch, which from the side appears as as a vertical column — A side view of the Gateway Arch is framed in the symmetry of a historic allée containing London planetrees.
NPS / M. Tack

At 630 feet tall, the Gateway Arch remains America’s tallest man-made monument. Located in St. Louis, Missouri, the Arch stands adjacent to the Mississippi River in a park-like setting containing ponds, tree-lined allées, and a grand staircase. The cohesive modernist style of the structures and grounds resulted from the close collaboration of architect, Eero Saarinen and landscape architect, Dan Kiley.

The Saarinen/Kiley design was selected through an architectural competition organized by the Jefferson National Expansion Memorial Association (JNEMA) and National Park Service at the end of World War II. Originally, proponents of Jefferson National Expansion Memorial project envisioned it to honor President Jefferson, commemorate westward expansion, and support riverfront revitalization. The Gateway Arch construction concluded in 1965. The landscape design was implemented in several phases with the majority of development completed by 2003. After the completion of the Arch, the site grew in popularity as a tourist destination and the monument became an icon of St. Louis.

View of the Gateway Arch landscape from above includes a walkway curving around turf, construction, and a courthouse surrounded by downtown St. Louis. — Construction of the visitor center seen from the top of the Gateway Arch in November 2017. The view in this direction also includes the Old Courthouse surrounded by buildings of St. Louis, and the park-like landscape.
NPS / L. Edwards

In 2018, the park underwent a name change from Jefferson National Expansion Memorial to Gateway Arch National Park. The change acknowledged and addressed a need to provide a more inclusive narrative of American history. The on-site visitor center and museum interprets regional and local history, including Native American history, European settlement and westward expansion, St. Louis history, and the design and construction process of the Gateway Arch and grounds. This history includes the memorial’s original purpose as well as its architectural, landscape architecture, and engineering significance.

The National Park Service manages Gateway Arch National Park and an adjacent historically significant property known as the Old Court House. An inholding property, the Parish of St. Louis – also referred to as the Old Cathedral – was completed in 1853 before construction of the monument and is owned and managed by the Archdiocese of St. Louis.

Landscape Description

The curved entrance to the museum in the embankment under the Gateway Arch — The underground entrance to the museum and visitor center at Gateway Arch National Park.
NPS / M. Tack

The National Expansion Memorial landscape consists of 91 acres to the west of the Mississippi River. Leonor K. Sullivan Boulevard along the Mississippi River delineates the eastern site boundary and the depressed Interstate 70 defines the majority of the western boundary. A 2017 extension over Interstate 70 provides pedestrian access to Luther Ely Smith Park and the Old Courthouse, site of the landmark Dred Scott case. The extension reinforces the original vision of an axial relationship between the courthouse and arch. The underground visitor center and museum containing the Arch tram entrance also lies on this axis. The tram ride to the top of the Arch is a popular visitor activity that allows for a bird’s eye view of the landscape.

The National Expansion Memorial landscape merges grasses, trees, open turf, and curving walkways — New North Gateway public use area at Gateway National Park.
NPS / L. Edwards

The Cultural Landscape falls to the east of I-70 and follows the original “forest and meadow” design concept. The large number of London Planetrees (Platanus x acerifolia) lining the allées and the groves of Bald Cypress trees (Taxodium distichum) contrast with the open spaces around the two ponds. The rolling hills around the ponds work with the vegetation to frame essential views of the Arch. The same catenary-curve geometry of the Arch repeats in the topography and curving walks. Even the levee-side grand staircase references the geometry through its sweeping shape created by the steps’ decreasing depth. These landscape features and details strengthen the visual relationship between the Arch and its surroundings.

Gateway Arch National Park has integrity in design, location, materials, workmanship, setting, feeling, and association. The site has the ability to convey its historical significance, as both a memorial and major designed landscape of the NPS. The landscape’s current and historic location in St. Louis strongly contributes to its integrity related to the memorialization of westward migration. The purpose for its creation corresponds to the city itself. Gateway Arch National Park’s other area of significance – its design merit as a work of two recognized masters in their professions — is upheld by attentiveness to the original Saarinen/Kiley design intent. Although some features were not constructed as designed and compatible substitution of plant material occurred, the overall design concept was realized.

Historic Use

After the establishment of St. Louis as a French fur-trading post in 1764, the village continued to grow into a thriving town. St. Louis’ geographic centrality and proximity to the confluence of the Missouri and Mississippi Rivers made it an ideal hub for steamboat and river commerce. Following President Thomas Jefferson’s 1803 Louisiana Purchase, St. Louis also served as a prominent departure or “jumping-off” point in westward migration. Although the Lewis and Clark Expedition did not begin in St. Louis, it sourced supplies from the city and returned to it in 1806. In 1822, St. Louis was incorporated as a city.

By the late 19th century river commerce declined in favor of rail transportation, which resulted in the deterioration of the St. Louis riverfront. The riverfront memorial proposal, championed by attorney Luther Ely Smith, intended to revitalize the riverfront and commemorate President Jefferson and westward expansion. After the proposal’s favorable reception in 1933 by St. Louis Mayor Bernard Dickmann and local leaders, the Jefferson National Expansion Memorial Association (JNEMA) formed to develop plans and secure funding. In 1935, President Franklin D. Roosevelt signed an executive order which enabled the Secretary of the Interior to develop the memorial, with funds allocated by Congress, and to establish the site location. Early planning studies conducted by the NPS identified buildings worthy of preservation. These included the Old Courthouse and the Old Cathedral. Issues related to land acquisition and funding delayed the project until the end of World War II. In January 1945, JNEMA formally announced an architectural competition for the memorial design.

Historic American Landscapes Survey drawing shows tree-lined lawn, scattered trees, and curving pond — Vegetation recorded at Jefferson National Expansion Memorial for Historic American Landscapes Survey (HALS MO-6).
Historic American Landscapes Survey, Library of Congress

A path alongside a designed pond, encircled by trees and turf with the Gateway Arch rising in the background. — The curving design of the Arch and the landscape features.
NPS / M. Tack

Architect George Howe served as the professional advisor of the competition. He, along with Luther Ely Smith and the JNEMA worked to develop guidelines and programmatic requirements for design proposals. By the September 1, 1947 deadline 172 entries were received and five finalist selected. Among the finalists was Design Number 144 by Saarinen, Saarinen and Associates for an immense arch. The collaborative team, headed by Eero Saarinen, included J. Henderson Barr, associate architect, Dan Kiley, landscape architect, Alexander H. Girard, painter, and Lily Swann Saarinen, sculptor. The second stage of the competition concluded on February 18, 1948 with announcement of the winning design.

The jury assessment said of the design: “It tends to have the inevitable quality of a right solution. The monument suggests the historic past of St. Louis as the Gateway to the West. It is large in scale, yet does not dwarf other structures, and by its very form is sympathetic with the Old Courthouse dome.” The 1959 NPS Master Plan for the memorial adapted the Saarinen/Kiley design and groundbreaking ceremonies occurred on June 23, 1959. Construction of the Gateway Arch was completed on October 28, 1965. Landscape development occurred in phases with walkway and Rosehill ash tree installation in 1972. The last major construction project, the grand staircase, was completed in 2003. Although less than 50 years old at the time of its evaluation, the Arch was listed on the National Register of Historic Places for its “exceptional importance” and designated as a National Historic Landmark.

A man in a suit descends a full-size model staircase next to a two story modern style building, — Mock up of stairs for Gateway Arch (between 1947-1965).
Balthazar Korab collection, Library of Congress

In 2010, the Gateway Arch Park Foundation organized The City + The Arch + The River international design competition centered on St. Louis downtown revitalization. The implementation of the winning Michael Van Valkenburgh Associates design improved pedestrian accessibility over Interstate 70, expanded exhibition space, and transformed the former parking garage into public space. In addition, the design planting plan identified London Planetrees (Platanus x acerifolia) to replace ash trees in the historic allées due to their susceptibility to Emerald Ash Borer. Despite these contemporary changes and compatible substitutes, the historic Saarinen/Kiley design concepts remain highly legible in the landscape. Gateway Arch National Park provides an exceptional example of Modernist architectural and landscape design.