Brethil is a fictional forest in J.R.R. Tolkien's Middle-earth, specifically located in the region of Beleriand. It is known for its dense trees and rich wildlife, providing a natural habitat for various creatures. The forest is significant in the lore of The Silmarillion, where it serves as a refuge for the Edain, a group of Men. The forest of Brethil is also home to the Haladin, a branch of the Edain who settled there. Notable events in Brethil include the tragic tale of Túrin Turambar, a central character in Tolkien's stories, whose life is deeply intertwined with the fate of the forest and its inhabitants.