South City (referred to in the manga as the "South Capitol") was mentioned by Future Trunks to Goku of where the future battle with the androids would take place. There is an island called Seismo nine miles south west of this city, suggesting it is on the coast.
An area of South City was turned into a wasteland by Dr. Kochin and Wheelo's machine.
In the Dragon Ball Zepisode "Our Hero Awakes", a news report mentions Cell attacking the city.