Not much is known about the actual landscape of the island only that it was covered with green grass, but there may have been a dwelling of a sorts there.
Almaren was raised sometime after the retreat of Melkor when the earth had become firm and flat. It was at this 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.