Who is Elrond’s father in J.R.R. Tolkien’s legendarium?

Elrond’s father in J.R.R. Tolkien’s legendarium is Eärendil.

Eärendil the Mariner is the son of Tuor, a Man, and Idril, an Elf of Gondolin. He marries Elwing, who is descended from both Elves and Men, and they have twin sons: Elrond and Elros. Because of this ancestry, Elrond and Elros are given a choice between the destinies of Elves and Men.

Elrond chooses to be counted among the Elves and later becomes the lord of Rivendell. Elros chooses the fate of Men and becomes the first king of Númenor. Their different choices establish a major ancestral division that echoes through the histories of Middle-earth and Númenor.

Eärendil’s voyage to Valinor is central to the ending of the First Age. He pleads for help against Morgoth, and afterward he is placed in the sky as the star associated with the Silmaril carried by his ship.