38-year-old Siobhan Hutcheon, from Ardmore in Muff, died in the incident that involved a car and a bus.
It happened at about 330pm yesterday afternoon on the road between Letterkenny and Derry.
Two other children remain in a stable condition in Altnagelvin Hospital in Derry.
The Belfast Trust said the child was in a stable condition in the Royal.
The driver of the bus was not injured.