Hallett is a small town in Mid North region of South Australia, situated on the Barrier Highway and former Peterborough railway line 32 kilometres (20 mi) north of Burra and 38 kilometres (24 mi) south-east of Jamestown, Hallett lies close to Goyder's Line, plotted in the nineteenth century by George Goyder, separating the land suitable for cropping from the land suitable for grazing. At the 2011 census, Hallett shared a population of 235 with adjoinig localities.
The town of was named for pioneering pastoralist and politician John Hallett, and laid out on his property "Willogoleechee". The first were offered for sale on 7 July 1870. Hallett Cove was also named for him.
Once a railhead for the local farming community, the town today features a store, gallery and the friendly Wildongoleechee Pub.
The historic Cappeedee Homestead and Woolshed is listed on the South Australian Heritage Register.
Hallett is the closest town to Mount Bryan East, birthplace of Sir Hubert Wilkins polar explorer, ornithologist, pilot, soldier, geographer and photographer (1888–1958), perhaps the last modern explorer. Sir Hubert Wilkins birthplace and childhood home, Netfield, now restored as a historic site, is easily accessible from the renowned Mount Dare Driving Circuit between Hallett and Terowie.