The Old Courthouse in downtown St. Louis was the site of many events that had national repercussions. For example, in the 1840s and 1850s, the courthouse's rotunda was an arena for great speeches, debates, and discussions on the possibilities of building railroads across the continent. During this same period, one of the courtrooms was the setting for the portentous Dred Scott trial.

The courthouse as it exists today took nearly 40 years to complete. The original brick structure built in 1828 soon became too small for the growing city of St. Louis. A classical Greek Revival design that incorporated the brick courthouse as its east wing was opened on Washington's birthday, February 22, 1845. Throughout the years the courthouse continued to be remodeled and enlarged. The brick east wing was eventually replaced and another larger, more elaborate dome was designed and constructed. Not until July 4, 1862 was the courthouse declared officially complete. It was the tallest and most impressive building in St. Louis, rising more than 190 feet.