Karanja is a rural locality in the local government area (LGA) of Derwent Valley in the South-east LGA region of Tasmania. The locality is about north-west of the town of New Norfolk. The 2016 census recorded a population of 28 for the state suburb of Karanja.
Karanja was gazetted as a locality in 1959. Karanja is a city in India, named after Saint Karanj. Three ships of this name, and this locality, appear to have been named from this source.
The Tyenna River forms the north-western boundary. The Derwent Valley Railway line forms part of the northern boundary before passing through to the south-west.
Route B61 (Gordon River Road) runs along the southern boundary. From there Karanja Court provides access to the locality.