Bilbo Baggins is 111 years old at the start of his eleventy-first birthday party in The Lord of the Rings.
The party opens The Fellowship of the Ring, the first volume of Tolkien’s trilogy. Bilbo’s unusual phrase “eleventy-first” means his 111th birthday, not his 110th or 101st. The celebration takes place in Hobbiton and is also the occasion for Bilbo to leave the Shire.
Bilbo’s remarkable age is important because hobbits are portrayed as long-lived compared with humans. His longevity also helps explain why his younger cousin and heir, Frodo, is already an adult before beginning the quest to destroy the One Ring.
The birthday party is more than a cheerful opening scene. It introduces the Shire, establishes Bilbo’s connection to the Ring, and launches Gandalf’s investigation into its true nature. Tolkien later developed Bilbo’s earlier adventure in The Hobbit.