The Old Courthouse is a treasured, historical landmark located in downtown Saint Louis. It is no longer functioning as a court house because it was replaced by the Civil Courts building in 1940. It is now an extension of the Jefferson National Expansion Memorial. Construction on the Old Courthouse, as it is today, began in 1839. In the 1820s there was a courthouse on the site which was remodeled and added to by Henry Singleton. Later, Robert S. Mitchell demolished the old east wing, remodeled Singleton's west wing, and added large annexes at the north and south ends. He maintained the Greek Revival architectural style. During the Civil War, William Rumbold added an Italian Renaissance dome which was a precursor of the dome on the United States Capitol in Washington D.C. Historically, this was the first cast-iron dome completed in the United States.
The Old Courthouse was the setting for the 1847 and 1850 trails of Dred Scott. Murals painted by Carl Wimar, adorn the walls of the rotunda making it one of the most striking features of the building. There are also museum galleries that feature exhibits on St. Louis history. There are also two restored courtrooms that are open to the public.
The location of the Old Courthouse is 11 North 4th Street in downtown St. Louis. The building was designated a city landmark in June 1966.