The fictional island home of J.R.R. Tolkien’s Númenóreans is Númenor.
Númenor is an island kingdom in Tolkien’s Second Age. The Valar raised it from the sea as a reward for the Men who had fought beside the Elves and the powers of the West against Morgoth during the First Age.
The Númenóreans were granted unusually long lives and became renowned as sailors, builders, and rulers. Their growing fear of death eventually fed resentment toward the Valar, especially under kings who rejected the limits placed on human life.
The island was destroyed in the Downfall of Númenor after its king, Ar-Pharazôn, attempted to challenge the divine powers. Survivors led by Elendil reached Middle-earth and founded the kingdoms of Arnor and Gondor. Tol Eressëa, Balar, and Almaren are separate locations in Tolkien’s mythology.