The Dark Tower Wiki

The Great Western Woods are a huge woodland located in Mid-World. The woods are north of the Western Sea and west of rolling plains of The River Barony. The Turtle-Bear Beam is located in these woods and is guarded by the guardian known as Shardik. The woods appear to be mountainous in parts aswell.

DT3 2

Roland and Susannah in the Great Western Woods

During the third volume of the Dark Tower tale,  Roland and his new companions Eddie Dean and Susannah Dean are training in the ways of the Gunslinger in the woods after traveling for a great long time along the beach of the Western Sea. In the woods they encounter the Shardik and manage to destroy him after he attacks Eddie. Roland then discovers the Beam.

It is stated by Roland that the woods are very, very old. Shardik had inhabited the woods for along, guarding the entrance to the Turtle-Bear Beam. In addition, there were also groups of forest tribes that used to inhabit the woods, constantly living in fear of Shardik, whom they called Mir. However, the Ka-tet does not encounter them.