Police and a bystander are being credited with rescuing a woman after a crash that left her trapped in her partially-submerged vehicle in a swamp.

Police say the woman was running out of breathable air space and trapped in the car, which was upside down in the swamp on Grey Road 4, just west of Flesherton.

Officers responded to a call Saturday at about 8 a.m. saying a vehicle had left the road, rolled, and was partially submerged.

Const. Gab Kokas and a bystander went into the frigid water and found the woman strapped into her seat by the seat belt. As the vehicle continued to fill with water, the officer was able to open the door and, with the help of the other person, free the driver.

Catherine Miller, 58, of Grey Highlands, was taken to Markdale Hospital where she was treated for minor injuries and released.

OPP are thanking those who helped at the scene.

- With files from CTV London