Dorga is found up the river, surrounded by some envy drakelings. Be careful when you attack it, since the drakelings will help it out. She is located NorthWest of the crab bridge near Ft. Atla (by Nisse's Lair), at 32k, 43k.
There is an encampment of Envy drakelings and
the Droga wanders around here with one smaller drake in tow. You will always
get both when you pull it.