One of the oldest forests in Middle-earth, Fangorn was situated to the southeast of the Misty Mountains, just north of Rohan. It was a dark and menacing wood, unsafe for anyone who would threaten the trees.

In the Third Age, Fangorn became the sole home for the Ents, the Tree Shepherds, and took its name from the eldest Ent, Fangorn (Treebeard).

The forest was home to many Ents and Huorns, that are able to move in shadow and attack those that threaten the forest.

After the Battle of Isengard, in which Isengard was turned by the Ents into the Treegarth of Orthanc, the Ents and Huorns returned to Fangorn.