Crystal Brook is a town in South Australia, named after the spring-fed creek next to which it was founded. It is 197 kilometres (122 mi) north of Adelaide and in 2006 had a population of 1,185.
Crystal Brook is situated on Goyder's Line near the border of two climate systems. While apparently cold semi-arid, the town benefits from a temperate mediterranean climate zone near to the east, making possible slightly more intense farming in the region. To the west and north-west lies some marginal, semi-arid farmland. The local farming community still supports many small businesses in the town.