Andúnië was an important city and port in the realm of Númenor, located on the Bay of Andúnië in the Andustar region, on the western end of the island. Though not the capital, it was initially the largest city of Númenor because the Elves of Tol Eressëa would often visit the haven. The city was home to the Lords of Andúnië descended by Valandil, the highest nobles of Númenórë, who were leaders of the Elendili (also known as The Faithful).
Andúnië is a variant of the Quenya word andúnë, meaning “sunset”.
In S.A. 630, Tar-Elendil created the title Lord of Andúnië in honor of his first grandson, Valandil. A distaff branch of the line of Elros, the Lords of Andúnië were important nobles and members of the Council of the Sceptre. Since Andúnië was an Elf-haven, the Lords of Andúnië were also the leaders of the “Faithful" — those who advocated continued friendship with the and obedience to the Valar.
However, as the Shadow was falling upon Númenor, Armenelos became larger and more important than Andúnië. By the close of the Second Age, the Faithful were labeled as traitors by the King’s Men and deported to Rómenna in the east. Andúnië was ultimately destroyed in the Downfall of Númenor in 3319.
Amandil, the last of the Lords of Andúnië, was the ancestor of the Kings of Arnor and Gondor in Middle-earth.