The main N15 Ballyshannon to Donegal Town road has been closed following a serious crash last night.
The collision occurred at around midnight between the Erne roundabout and Ballintra, close to McCafferys Quarry.
It is not yet known how many people were injured.
Gardaí continue to work at the scene and the road is expected to be closed for most of today (Wednesday).
Diversions are in place via The Ross (R231).