The incident happened around at 12.30am when a car left the Glen Road in Glenties.
The vehicle hit and tree and ended up on its side in a nearby field.
Glenties Fire Brigade crews attended the scene and assisted with the recovery of the driver.
Ambulances from Killybegs and Glenties Gardai also attended the scene.
The driver, who was is a foreign national, was transferred by ambulance to Letterkenny General Hospital in a serious condition.