This building of locally-quarried granite ashlar sits in downtown Union next to the Union County Courthouse. It was constructed as a jail in 1823 by renowned architect Robert Mills, a Charleston native who served as State Architect and Engineer for the South Carolina Board of Public Works from 1820 through 1830. During that decade Mills, who had previously worked on structures in Philadelphia and was mentored by Thomas Jefferson, designed several public buildings around the state. Mills would go on to create his most famous work, the Washington Monument in Washington, DC, in 1836, though it would not be built until 1884.
Mills designed buildings ranging from some of South Carolina’s most revered courthouses and churches to county jails. In fact, it was Mills’ concept of jails that was most revolutionary. Mills rejected basement cells, or dungeons, claiming that not only did they make jails vulnerable to prisoner escapes, but that they were unhealthy for inmates due to lack of proper ventilation. The humane conditions of jails were an important feature of Mills’ designs, which included fireproof buildings as well as adequate air circulation. Other extant South Carolina jails designed by Mills include the Old Charleston Jail and the Lancaster County Jail.
A jail for Union County was already in progress when Mills joined the project. He preferred local granite as a building material – rather than the brick that was used prior to his arrival – and rebuilt the jail in the quarried stone. The two-story design featured an apartment for the caretaker which overlooked the jail. The second floor was originally reserved for hangings but was later converted to provide more cells.
Twentieth-century modifications to the jail include a one-story sheriff’s apartment and a two-story fieldstone rear addition containing administrative offices. Today the jail houses the Union County Sheriff’s Office.
The Union County Jail is listed in the National Register:
The Union County Jail, attributed to Robert Mills, is a two-storied, Palladian style structure of granite ashlar construction built in 1823. Mills’ work is characterized by the innovative technical aspects he employed in his designs for government structures. In prison design, he recommended that there be no basement dungeons due to their unhealthy nature and also because Mills felt that most breakouts occurred as a result of tunneling to the outside from a basement area. He also recommended that a caretaker’s apartment be placed to overlook the prison, an idea seen in the sheriff’s apartment at the Union Jail. Mills was interested in providing decent living conditions for prisoners. Buildings were to be made as fireproof as possible to insure prisoner safety. In the Union Jail, cells were to be one-roomed and were arranged to provide for adequate ventilation. The exterior of the jail has received two additions since 1900 and the interior has undergone extensive alteration.