Tol Eressëa, the Lonely Isle, was in origin an island that stood alone far out to sea. When the Elves of the Great Journey reached the eastern shores of the Great Sea, Ulmo moved the island, using it first to ferry the Vanyar and the Noldor into the West, and then returning for that part of the Teleri who wished to make the journey. After this second crossing, the island was grounded in the Bay of Eldamar, within sight of the coasts of Aman, and the Teleri remained there, becoming the original Eldar of Eressëa.

After an age on the island, these Teleri began to desire the Light of Aman. Taught ship-building by Ossë, they constructed a fleet of white ships that were drawn across the bay by swans, leaving Tol Eressëa abandoned for a time.¹

New settlers on the Lonely Isle arrived as the First Age came to its end. These were Elves of Beleriand, summoned into the West by the Valar,² and Tol Eressëa became their new home. These Elves arrived in very great numbers, and settled mainly in the city of Avallónë. Though the main influx of Elves took place soon after the defeat of Melkor, it continued for the next two Ages, as others of the Eldar chose to leave Middle-earth and make the Westward journey.

These Eldar of Eressëa dwelt in bliss for a while, becoming renowned for their wisdom, and for the White Tree Celeborn that grew in the centre of their island. They could at times visit Valinor if they wished, or sail eastward to Númenor, which lay close enough to Eressëa that its westernmost coasts could be discerned from the island. For many centuries the Eldar of Eressëa and the Men of Númenor were close in friendship, but as time passed the Kings of Númenor turned away from the Eldar, until Ar-Pharazón brought a vast fleet out of the east, surrounding Eressëa with his ships as he passed by to his doomed attempt to invade Aman.

After the Downfall of Númenor, the lands of the West, including Tol Eressëa were taken away from the physical world. Nonetheless it remained accessible to the Eldar, who could still reach it by sailing the so-called Straight Road, and so Elves of Middle-earth continued to join the Eldar of Eressëa even at the time of the War of the Ring.