The woman has been identified as Holly Jean of Mississauga, police said.
Jean was a passenger in the SUV, along with five other people when the crash happened Wednesday morning, police said. The other occupants were taken to hospital with non-life-threatening injuries.
Police initially said the victim was 58.
The crash happened about three kilometres east of Belleville, closing Hwy. 401 for about eight hours as police investigated.
The Napanee detachment of Ontario Provincial Police is asking witnesses to come forward.