Legolas Greenleaf is an Elf who was part of the Fellowship of the Ring in the Third Age. He is the son of the Elf-king Thranduil of Mirkwood, a Prince of the Woodland Realm (Mirkwood), a messenger, and a master bowman. With his keen eyesight, sensitive hearing, and excellent bowmanship, Legolas is a valuable resource to the other eight of the Fellowship. His age was never stated by Tolkien. Legolas became great friends with the dwarf Gimli , another member of the Fellowship, despite the long-held dispute between Elves and Dwarves.
It is not known whether Legolas was Thranduil's only son, or whether he was heir to his father's crown.
(description taken from The Lord of the Rings Wikia)