Parnaroo is a rural locality in South Australia, situated east of Peterborough. It shares the same boundaries as the cadastral Hundred of Parnaroo, which was established on 31 October 1878. It was reportedly named for an Aboriginal word meaning “rain of little stones”, which had been taken from a sheep run opened in the area in 1854. The modern locality was formalised in August 2000, and named for the long established local name.