In Middle-earth, the fantasy universe of J. R. R. Tolkien, Elendil was a heroic figure. Known as Elendil the Tall or Elendil the Fair, he was the father of Isildur and Anárion, last lord of Andúnië, and the founder and first king of Arnor and Gondor.

Elendil was born in 3119 of the Second Age in Númenor, son of Amandil, Lord of Andúnië and leader of the 'Faithful,' who maintained a strong friendship with the Elves and preserved the old ways against the barbarous practices of Ar-Pharazôn and Sauron. Elendil's name means either "Elf-friend" or "Star-lover" in Quenya.

Elendil, his sons Isildur and Anárion and their supporters fled to Middle-earth at the Downfall of Númenor, sailing east in seven ships and founding the realms of Arnor and Gondor in Middle-earth in 3320 S.A.. With them they took the palantíri, the "Seeing Stones" that were given to the Lords of Andúnie by the Elves of Tol Eressëa, and a seedling of Nimloth, the White Tree of Númenor.

As he landed on Middle-earth he proclaimed in Quenya: Et Eärello Endorenna utúlien. Sinome maruvan ar Hildinyar tenn' Ambar-metta, which means, 'Out of the Great Sea to Middle-earth I am come. In this place will I abide, and my heirs, unto the ending of the world.' His heir and many-greats nephew Aragorn spoke these words again when he took up the crown of Gondor as King Elessar at the beginning of the Fourth Age.

Elendil lived in Arnor, where he founded the city of Annúminas. His son Anárion founded the city of Minas Anor in Anórien, and his son Isildur founded Minas Ithil in Ithilien. Across the Anduin the city of Osgiliath was built. Across the realms were built towers for the palantíri, with which the realms kept contact.

In time the evil lord Sauron returned to Middle-earth, establishing a stronghold in Mordor, next to Gondor. In 3428 Sauron attacked, seizing Minas Ithil. Isildur fled north to his father, leaving Anárion in charge of Gondor. In 3434, King Elendil and Isildur returned south together with the Elven High King Gil-galad and their combined armies, in the Last Alliance of Elves and Men. At the end of the long siege of Barad-dûr, in the year 3441 of the Second Age, Sauron came out to personally do battle. Gil-galad and Elendil fought Sauron and cast him down, but were both slain, and Elendil's sword Narsil was broken when he fell. His son Isildur used the broken sword to cut the One Ring from Sauron's hand. Isildur was eventually betrayed by the Ring at the Gladden Fields and slain by orcs.

Elendil was a great warrior and a wise king, and a heroic figure among the Dúnedain and other Men of the West. Isildur built a tomb for his father on the summit of the beacon hill of Halifirien. Aragorn's battle-cry was the name 'Elendil.'