The Hinterlands was once a great forest and wild region of Sadr and still is to most extents. With the rise of the tribal nations and unification of the elves to form Corcaigh and Aontoim, the Hinterlands became anything know either further west or further south of the great nations.
Many tribal inhabitants roam the hinterlands and southern mountains. Few have ventured deep, though the ocean on the far side of the mounts has been charted, though it has served little purpose. Some, but not all, of the wandering tribes (or settled ones for that matter) are friendly or indifferent. However, some are ravenous tribal packs of gnolls and goblinkind. While not inherently evil, they will defend their lands to the death.
Strange things have been reported to have happened in the woods and the elves believe the wilderness are controlled and protected by great spirits.