Tol Withernon or Isle of the Forgotten, was a mysterious and rarely spoken-of isle, said to lie off the eastern shores of Tol Eressëa, beyond the sight of most mariners who ventured upon the Sundering Seas. Though its existence was known to some among the Eldar and the loremasters of Númenor, few ever set foot upon its shores, and even fewer returned to tell of what they had seen.
The island was said to be shrouded in mist, appearing and vanishing with the tides, as if it were half in this world, half beyond it. Some among the Eldar whispered that Tol Withernon was a place of quiet refuge, where those who had grown weary of the sorrows of Arda might find solace before passing beyond the Circles of the World. Others, especially among the Dúnedain, believed that it was a threshold to the West, a place where those who sought Aman but were unbidden might linger, neither wholly rejected nor truly accepted.