And then on again through the Folde; and through the Fenmarch, where to their right great oakwoods climbed on the skirts of the hills under the shades of dark Halifirien by the borders of Gondor; but away to their left the mists lay on the marshes fed by the mouths of Entwash.
- The Return of the King (Book 5), Chapter 3
The Mouths of Entwash is a mighty delta formed where the River Entwash meets the River Anduin. The marsh shields the kingdoms of Gondor and Rohan from the wild lands to the north.