South Nietta is a rural locality in the local government areas (LGA) of Central Coast and Kentish in the North-west and west LGA region of Tasmania. The locality is about south of the town of Ulverstone. The 2021 census could not record a population for the state suburb of South Nietta because the population was too low.
South Nietta was gazetted as a locality in 1965.
The Lea River and the Wilmot River together form most of the eastern boundary.
Route C129 (South Nietta Road) enters the locality from the north.