Bilbo and Frodo Baggins celebrate their birthdays on 22 September in J.R.R. Tolkien’s Middle-earth.
Bilbo was born on 22 September 2890 of the Third Age, while Frodo was born on 22 September 2968. Their shared birthday becomes especially important in The Lord of the Rings because Bilbo’s eleventy-first birthday party also marks his farewell from the Shire and Frodo’s coming of age.
The date can cause confusion because Tolkien’s chronology uses the Shire Reckoning and the calendar of Middle-earth rather than modern historical dating. The year numbers differ, but the day and month remain 22 September. The date is also celebrated in the real world as Hobbit Day, usually during Tolkien Week, although modern fan observances are commemorations rather than events described inside the novels.