The northbound lanes of Highway 400 at the Highway 11 interchange were closed for about four hours on Monday evening as OPP investigated a motorcycle crash in which the rider was ejected.
Police say he was airlifted to a Toronto hospital with life-altering injuries.
The northbound lanes were closed until 11 p.m. for the investigation.
Orillia OPP is asking any witnesses who have not already spoken to police or have dash cam footage of the collision to contact them at 705-326-3536 or 1-888-310-1122.