• Looking up at the Gateway Arch


    National Expansion Memorial Missouri

Park Purpose and Significance


The park commemorates, through a designed memorial, the vision of Thomas Jefferson for building a unified continental nation and St. Louis’ role as a confluence and gateway in the westward expansion of the United States during the 19th century. The park promotes an awareness of key individuals and cultural groups involved in exploring, exploiting, and inhabiting the western lands from the Mississippi River to the Pacific Ocean.

The park preserves the architecturally significant Old Courthouse as the site of the Dred Scott case, which divided North and South over the extension of slavery into the western territories and led to the American Civil War.


St. Louis was politically and geographically pivotal in the westward expansion of the United States during the 19th century. Significant historic events occurred at the site, including the transfer of the Louisiana Territory from Spain to France to the United States; the scene of the negotiation of numerous treaties removing Indian tribes from their lands; and the provisioning of the Lewis and Clark expedition and their return. St. Louis was the starting point for numerous explorers, fur traders, overland pioneers, and others who made the westward journey.

In 1847, Dred and Harriet Scott sued for their freedom from slavery at the Old Courthouse in St. Louis. This historic case, argued in 1847, 1850, and 1854, and the subject of a U.S. Supreme Court decision in 1857, determined that all people of color, enslaved or free, could not become citizens of the United States; and removed restrictions on the extension of slavery into the U.S. Western territories, further dividing the North and South and eventually leading to the Civil War.

The Old Courthouse is a prime example of mid-19th century Greek Revival courthouse design, and includes an Italian Renaissance style cast iron dome that predated the completion of the national capitol dome in Washington.

The memorial is recognized globally as an exceptional example of mid-20th century Modern design. The soaring Gateway Arch is one of the world’s great architectural and engineering achievements, a tangible symbol of St. Louis’ historical role as the “Gateway to the West.” The site is recognized as a deliberate built experience, a complete design for a public monument, and a masterpiece of integrated composition of structure, landscape and interpretation.

The museum objects and archival records in the park’s collection document the westward expansion of the United States, and the creation, planning, and building of the memorial. The collection is used in ongoing research by scholars and staff and is the basis of the historic site’s interpretation programming and museum exhibits.

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