Athelstone /ˈæθəlstən/ is a suburb of Adelaide in the City of Campbelltown. It was established in the 19th century but only became part of suburban Adelaide in the second half of the 20th century.
It is approximately 10 km north-east of Adelaide's central business district. The main arterial road, Gorge Road, runs through this suburb in an east-west direction. The River Torrens, one of Adelaide's major water supplies, borders the suburb. This water source runs its way from Mount Pleasant to the sea. Gorge Road leads up into the Adelaide Hills, joining the gorge of the Kangaroo Creek Dam, and the Torrens' source. Fifth Creek (a tributary to the River Torrens) also runs through the suburb as an intermittent stream, prone to flooding in late Spring (October–December).
Athelstone is bounded by the River Torrens, Black Hill Conservation Park, Montacute Road, Stradbroke Road, Hamilton Terrace, Schulze Road and River Drive.