Fangorn

In J. R. R. Tolkien's Middle-earth, Fangorn is the Sindarin name of the Ent 'Treebeard'.

The Fangorn Forest, where he and the other Ents live, is named after him.

Warning: Wikipedia contains spoilers

Meriadoc Brandybuck and Peregrin Took pass this forest in the second volume of The Lord of the Rings, The Two Towers. There they meet Gandalf again and travel to Helm's Deep with the Ents.