(Q. "blessed") An island in the Great Lake, the home of the Valar in the middle of Arda. The precursor to Valinor. It was at the place where the light of the Two Lamps mingled. Almaren was attacked and damaged by Melkor, and the Valar moved far to the West, to Valinor. According to some traditions, the island of Almaren survived the attack, and was the same island as Tol Eressëa.
(Q. 'outside Aman') The northern coastlands of Aman, north of Valinor, that lay outside the mountain-fence of the Pelóri. It was deserted, mountainous and frozen (arguably, tundra). To the north lay the Helcaraxë which (in the First Age) joined it with Middle-earth, and this was the way Melkor, and later the Noldor took after their Exile.
In this area was Hanstovánen, the location where the Noldor stopped on their journey and heard Mandos's Prophecy of the North, pronouncing Doom on the Noldor for the Kinslaying and rebellion, and warning that if they proceeded they would not recover the Silmarils; moreover that they all will be slain or tormented by grief. This is where Finarfin and many of his people turned back and returned to Tirion, where Finarfin continued to rule the Noldor who remained in Aman.
The easternmost city on Tol Eressëa and the Haven of the Eldar. It was founded either by the Teleri during their long stay there, before they left the island for Alqualondë, or more probably by the Elves returning from Middle-earth after the War of Wrath. In any case, it became the chief dwelling of the Noldor and Sindar, as they were not allowed or unwilling to resettle in Valinor.
The city became the symbol of the Blessed Realm to Men, as before on cloudless days one could see the tower of Avallónë from the Meneltarma in Númenor. After the fall of Númenor and the changing of the world, Avallónë became the port of arrival for ships taking the Straight Road. It is said that the Master Stone of the palantíri was placed in Avallónë, and that Elendil often looked that way desiring to see the Lost West.
Tolkien was apparently evoking the island of Avalon in the legend of King Arthur, although the form Avallónë literally means "near Valinor" in Quenya; compare this with Atalantë, the name of Númenor evoking Atlantis. Moreover, in Tolkien's writings originally Avallon was a later name for the island of Tol Eressëa, not for the haven.
Avathar, being eaten away by the sea, was narrower than Araman, a similar region lying to the north of the Bay of Eldamar. But Avathar was a darker land; indeed it is accounted that there "the shadows were deepest and thickest in the world". This is the source of its name, which means 'Shadows' in ancient Quenya.