Lost Woods is located through Whiland. Like the name implies, Lost Woods is easy to get lost in as there are no visible paths. The whole of the map has small "sections" which are encompassed by Fir Tree. Lost Woods is home to many of the same mobs found in Whiland. It is also home to other mobs such as: Archdevil, Ettin King, and Behemoth. Three bosses can also be found in Lost Woods: Cave Crawler, Giant Cyclops, and Venus Flytrap.
Check the entire Monsters list.