Fayette County is one of five counties created in 1821. It is home to the only preplanned community in Georgia, a 16,000-acre community called Peachtree City, which was chartered in 1959. Part of the Atlanta metropolitan area, it has experienced significant population growth since the 1970s.

From 1828 to 1858 Georgia created four new counties from Fayette County land: Campbell (later Fulton), DeKalb, Spalding, and Clayton, leaving Fayette County with its current area of 197 square miles.

The 1825 courthouse, the oldest courthouse building in the state, has undergone several restorations and is listed on the National Register of Historic Places. In 1888 a clock tower was added. The interior was renovated in 1965 and again in 1983, after an arson that did major damage.

The courthouse was fully restored in 1983-84 and now houses the chamber of commerce and the Fayette County Development Authority. The original 58-foot-long pine courthouse bench was removed and is now on view outside the south entrance. The current courthouse, called the Justice Center, was completed in 2003.

The Holliday-Dorsey-Fife House, built in 1855 by John Stiles Holliday, uncle of the famous gambler John Henry "Doc" Holliday, is located near the Old Courthouse Square. The house contains a number of items pertaining to Fayette County history, as well as a display of Civil War items.

The former Margaret Mitchell Library, built in 1948, is today the home of the Fayette County Historical Society and houses Civil War and genealogical records. Another place of interest is the fountain in Heritage Park, which was dedicated during the 1996 Olympic Games.