The Forbidden Lands are located in Tiquanda, east of Banuta (here) behind a great palisade. There are large and mysterious footprints, and some terrible and giant monsters beyond the wall. In this dangerous land, you can find Behemoths, Giant Spiders, Stone Golems, Massive Earth Elementals, Spit Nettles, Carniphilas and Hydras and if you listen carefully, you can hear whispers of The Blind Prophet.
There is a Behemoth cave near the stairs.
There is a Hydra cave near the coast in the east about halfway up north.