An Ontario Provincial Police news release says that just before 3:30 a.m. Sunday, two people were found trapped inside a vehicle in a drainage ditch on McLaughlin Road, north of The Grange Side Road.
The vehicle was found rolled over, police say.
Both occupants were extricated from the vehicle and rushed to hospital.
A female passenger was pronounced dead in hospital. The OPP have identified the victim as 29-year-old Stacy Capecchi of Toronto.
The male driver is in stable condition.
Police are still investigating the crash. No charges have been laid so far.
Anyone with information is asked to contact Sgt. Andrew Kinapen at 905-584-2241.