The fictional island kingdom whose people descended from the Edain in J.R.R. Tolkien's world was Númenor.
Númenor was given to the Men who had remained faithful to the Valar and had fought alongside the Elves in the wars against Morgoth. The first king was Elros Tar-Minyatur, the half-elven brother of Elrond, who chose the fate of Men.
The island lay in the Great Sea between Middle-earth and Aman. Its inhabitants enjoyed unusually long lives and developed a powerful maritime civilization. Over time, however, their fear of mortality produced resentment toward the immortal Elves and the Valar.
Númenor's destruction became one of the defining events of the Second Age. Survivors led by Elendil founded the realms of Arnor and Gondor in Middle-earth, linking the island's history directly to Aragorn and the royal line featured in The Lord of the Rings.