The A303 in Wiltshire was closed for more than four hours on Saturday following a fatal accident.
Two women were taken to hospital after a Land Rover left the road and hit a tree. One died later from her injuries.
The crash happened on the westbound side near the junction to Wylye.
The woman who died had suffered serious head injuries and was taken to Salisbury District Hospital by an ambulance with a police escort.
Another woman with chest and shoulder injuries was taken to the hospital by air ambulance.
Police said that the reason why the Land Rover, travelling from the London area to Exeter, went out of control was not clear.
They have appealed for witnesses.