 "Mill's Reef" Post Office opened on 1 February 1905 and was renamed "Alonnah" in 1909.At the , Alonnah had a population of 302.Alonnah is the main location in Bruny Island for government facilities, including post office, police station, primary school, internet centre, community library, pharmacy, and health centre with nurses, a visiting doctor, physiotherapist, and other health practitioners.