South Otago is dominated by three main topographic features: forests, hill country, and floodplains.
With the exception of the flat, fertile floodplains, South Otago is quite sparsely populated because of relatively cold winters, geographical isolation and lack of a decent port.
There are a number of rivers flowing through South Otago, the largest being the Clutha / Matau-Au, the country's second longest river, which flows from Lake Wānaka in Central Otago for 340 kilometres, through Balclutha (Scots Gaelic for "Town on the banks of the Clyde") and there splits in two around the large delta island of Inch Clutha before reaching the Pacific Ocean.
A significant west-flowing tributary is the Tuapeka River, starting point of the 1860s Otago gold rush near Lawrence.
Later, the main Māori tribe from the area, Kai Tahu, received a large cash settlement from the New Zealand Government as reparation for the confiscation of land that took place during that colonisation period.
The Otago gold rush of the 1860s, initially centred around Lawrence, drew thousands of men to the district in search of wealth.
The discovery of coal at Kaitangata was also important for the regions development, and was also responsible for one of Otago's worst disasters, an explosion at the mine in 1879.
The northern part of South Otago, including much of the Taieri Plains, is now within the boundaries of Dunedin City (the rest of the area is almost entirely within Clutha District).
South Otago is also home to Lake Mahinerangi, Dunedin's most important reservoir, which is located close to the top of Maungatua.