Mannahill (sometimes known as Manna Hill) is a settlement on the Barrier Highway and Indian Pacific railway line in South Australia. Mannahill is in the Northeast Pastoral district and is one of the easternmost settlements in South Australia. The population of Mannahill is 66 persons: 42 males and 24 females.
Mannahill was located on the stock route that passed from the Barrier Ranges in New South Wales to the then rail head at Terowie. The village also supported early gold mining activity at Mannahill and at Wadnaminga to the south. Mannahill was surveyed in the mid-1880s as a water-supply and maintenance point on the Peterborough to Cockburn railway line which was completed in 1887. The railway station had been previously constructed in 1886.