Forest River
From Tolkien Gateway
The Forest River is a great river that flows through northern Mirkwood. It begins in the Ered Mithrin far to the north, and then flows south-east, diverging at points, until it is met by the Enchanted River near Thranduil's caverns. From there it continues eastwards to the Long Lake of Esgaroth, which it meets in the Long Marshes.
