The 37-year-old was the driver of a silver Ford Fiesta which left the B724, half a mile west of the village, at about 4.40 pm on Tuesday afternoon.
The car overturned and the man had to be freed from his vehicle by the fire service.
He was taken by air ambulance to Queen Elizabeth University Hospital in Glasgow, where police say he is in a critical condition.
Enquiries into the cause of the crash are underway.
