Eithel Ivrin was the springs that fed a lakeland at the feet of the Ered Wethrin, the Mountains of Shadow on the northern borders of Beleriand. Even into the early First Age, Ulmo himself guarded the springs, so that they remained unsullied and undefiled. It was here that Gwindor brought Túrin after he had mistakenly slain his friend Beleg, and the pure waters of Ivrin healed him of the madness of his grief.
The springs did not remain inviolate for all time. As the First Age drew on, Ulmo's powers were withdrawn from the north and Morgoth's strength grew. When Glaurung the Dragon passed by the Pools of Ivrin on his journey to attack Nargothrond, he destroyed their crystal purity forever.