Gateway Arch National Park is a national park of the United States located in St. Louis, Missouri, near the starting point of the Lewis and Clark Expedition. The national park consists of the Gateway Arch, a steel catenary arch that has become the definitive icon of St. Louis; a park along the Mississippi River on the site of the earliest buildings of the city; the Old Courthouse, a former state and federal courthouse where the Dred Scott case originated; and the 140,000 sq ft museum at the Gateway Arch. It is the smallest national park in the United States at 192.83 acres, less than 2% the size of the next-smallest, Hot Springs National Park.