The Bi-State Development Agency was established as an interstate compact between Missouri and Illinois in 1949. This compact created an organization that has broad powers in seven county-level jurisdictions. Bi-State operates five enterprises including the Gateway Arch Riverfront, Metro Transit, the St. Louis Downtown Airport, the St. Louis Regional Freightway and the Bi-State Development Research Institute.

The Gateway Arch is a 630-foot-tall (192 m) monument in St. Louis, Missouri, United States. Clad in stainless steel and built in the form of a weighted catenary arch, it is the world's tallest arch and Missouri's tallest accessible structure. Some sources consider it the tallest human-made monument in the Western Hemisphere. Built as a monument to the westward expansion of the United States and officially dedicated to "the American people", the Arch, commonly referred to as "The Gateway to the West", is a National Historic Landmark in Gateway Arch National Park and has become an internationally recognized symbol of St. Louis, as well as a popular tourist destination.