On September 21, 1847, Baton Rouge donated a piece of land for the Louisiana State Capital which would be built to resemble a gothic style castle.
In 1862, during the Civil War, Union Admiral David Glasgow Farragut captured New Orleans, during the Battle of New Orleans, and the capital of Baton Rogue soon after.
The Union troops first used the “old gray castle,” as it was once described, as a prison for captured Confederate troops. Later in the war, the castle was used as a garrison for African-American troops under General Culver Grover.
While used as a garrison the Old Louisiana State Capitol caught fire twice. After the second fire, the structure was abandoned by Union troops. By 1882 the state house was totally reconstructed by architect and engineer William A. Freret, who is credited with the installation of the spiral staircase and stained glass dome, which are the focal points of the interior.
The refurbished state house remained in use until 1932, when it was abandoned for the New State Capitol building. The Old State Capitol Building has since been used to house federally chartered veteran’s organizations, and the seat of the Works Progress Administration. Restored in the 1990s, the former Capitol Building is now a museum.
Currently, the structure is a U.S. National Park and serves as the Old State Capital Musuem which contains a comprehensive political history of the state.
Hamilton Historical Records 