The Allendale County Courthouse was listed in the National Registry of Historic Places on August 1, 2007. It is an important example of the public design work of Georgia architect, G. Lloyd Preacher. Allendale was the last county to be established in South Carolina. In 1919 Allendale was formed from parts of Barnwell and Hampton Counties, which were thought at the time to be too large to govern effectively. The new county needed a courthouse, and construction began in 1921. The architectural style is Neoclassical Revival with massive limestone columns.
Following a devastating arson fire in 1998, the interior of the building needed reconstruction and the exterior need rehabilitation.