The fictional forest inhabited by Ents in J.R.R. Tolkien’s Middle-earth is Fangorn Forest.
Fangorn lies at the southern end of the Misty Mountains, near Rohan and Isengard. It is home to Treebeard and other Ents, ancient tree-like beings who remember the long history of Middle-earth.
Merry and Pippin enter Fangorn after escaping from the Orcs who captured the Fellowship. Their meeting with Treebeard helps awaken the Ents to the destruction caused by Saruman’s industrial expansion. The Ents eventually march against Isengard and overthrow Saruman’s stronghold.
Fangorn is sometimes confused with Mirkwood, another major forest in Tolkien’s stories. Mirkwood lies farther east and is associated with the Woodland Realm and the Elvenking Thranduil. The Old Forest, near the Shire, is also distinct from Fangorn and contains a different, unsettling tree tradition.