South Korea was an Asian nation, which made up Korea with it's rival, North Korea. It was neighbored by the China to the west, Japan to the east, and North Korea to the north.
In the wake of Miracle Day, the North Korean regime viewed its population as immortal soldiers and began to mobilise troops along its border with South Korea. (TW: The New World)
In 2059, South Korea was part of the Bowie Base One mission, though there were no South Korean astronauts on the station. (DW: The Waters of Mars)