Glithui was a river in the West Beleriand during the Elder Days of Middle-earth. The Glithui was a tributary of the river Taeglin and began in the Ered Wethrin near Amon Darthir, which was beneath a dangerous pass that led out of Dor-lómin. It ran southward for about twenty-five miles where it met the Taeglin, according to the The Atlas of Middle-earth.