For questions about the "Undying Lands", the realm in *The Lord of the Rings* inhabited by Ainur and Elves, including Aman and the island of Tol Eressëa. Always use in conjunction with the [tolkiens-legendarium] and use with additional works tags where appropriate, for example, [the-lord-of-the-rings].

The Undying Lands were a realm inhabited by Ainur and Elves. The area included the continent of Aman and the island of Tol Eressëa. The ocean Belegaer separated the Undying Lands from the western shores of Middle-earth.

(Lord of the Rings Wiki)

Notably, in the Third Age, a party comprising of Círdan, Elrond, Galadriel, Gandalf, Frodo and Bilbo Baggins traveled to the Undying Lands following the events of The Lord of the Rings trilogy.

Map of the Undying Lands and Middle Earth (Source)