South City is the main military hub and cultural center for the southern region of Amestris. Located to the south of Dublith, it is a place famous for its sightseeing and tourist attractions.
In the manga, it first appears in Chapter 27, when Edward Elric rushes to the South Area HQ from Dublith in order to turn in his yearly assessment report before the deadline. He accidentally encounters Major Alex Louis Armstrong, who is acting as part of King Bradley's escort while the Führer inspects the facility. However, the next we hear of Southern Headquarters, the soldiers there have been conducting a rather bloody border war with Aerugo in the southern town of Fotset since 1911. In Chapter 52, when Mustang's group is forcibly disbanded by the Führer, Master Sergeant Kain Fuery is reassigned to South HQ, and from there to the front lines at Fotset. South City was also the center of an earlier border war with Aerugo in 1835 and may be a part of the Nationwide Transmutation Circle.
In the 2003 anime series, it is first mentioned by Frank Archer when he and Major Armstrong capture Wrath, who was subsequently taken there. The South City Headquarters are eventually stormed by Izumi Curtis in an attempt to rescue the Homunculus and a four-way battle between the State Military (with Envy disguised as King Bradley), the Elric brothers, Kimblee (where he and Bido were representing Greed's side) and Izumi ensues inside the building.
Instead of traveling to South City in the 2003 anime, Frank Archer and Envy (disguised as Bradley) would take over the Führer's role during the events at Southern Command.
Ed's visit to Southern Command in regards for his assessment exam is omitted from the 2009 anime.