Middle-earth is the primary fictional setting of J.R.R. Tolkien’s The Lord of the Rings.
In Tolkien’s legendarium, Middle-earth is a large region of Arda, the world created in his mythology. The Lord of the Rings follows events there during the Third Age, including the journey of the Fellowship and the War of the Ring.
Middle-earth is not the name of an entirely separate planet in Tolkien’s intended framework. Tolkien presented his stories as part of an imagined ancient history of our own world, though the term’s fictional geography includes places such as the Shire, Gondor, Mordor, and Rohan.
The name is sometimes confused with the setting of other fantasy works. Narnia belongs to C.S. Lewis, Westeros to George R.R. Martin, and Earthsea to Ursula K. Le Guin.