The Ontario Provincial Police closed the eastbound lanes of Highway 401 near the Odessa ONroute for an extended period of time Saturday.
A small sedan entered the highway at Gardiners Road in Kingston west bound in the east bound lanes.
Two vehicles were involved in the collision.
The driver of the vehicle traveling in the wrong direction was an 85-year-old female.
She was taken to hospital with critical injuries.
The other involved driver and passenger were uninjured.