The boy was found alive in the back of the car, while the 34-year-old woman who was driving was dead in the front seat.
Emergency services found the Mitsubishi crashed into a tree on Naracoorte Road, about 25km south of Bordertown, near Adelaide, at 8pm yesterday.
The woman was pronounced dead at the scene.
The boy was taken to hospital with minor injuries.
Naracoorte Road was closed while investigators examined the scene. It has since reopened.
The woman’s death is the 48th life lost on South Australian roads this year.
