The Maw of Arawn is a fissure in the caldera of Mount Arawn, the highest peak in Forlorn. The fissure leaks sickly yellow fumes.
It is the hiding place of the Horn of the Sacred Grove.
Ravenloft Gazetteer Volume I
Ravenloft Third Edition - p121
Castles Forlorn: The Weeping Lands - p28
Castles Forlorn: Melancholy Meetings - pp27-29
Ravenloft Gazetteer Volume I- p63