The N5 road between Castlebar and Westport remains closed to traffic this morning, following a single vehicle collision last night.
The crash occurred at about 11.45 pm at Sheeaune, Westport when a car veered off the road and hit a concrete fence.
A male passenger in his teens was seriously injured and was taken to Mayo University Hospital where his condition is described as critical.
The driver of car was also taken to hospital in Castlebar with non life-threatening injuries.
Garda forensic collision investigators are at the scene, and the road remains closed with diversions in place via Newport.
