Middle-earth is the main continent in J.R.R. Tolkien’s writings about the setting of The Hobbit and The Lord of the Rings.
The term refers to the inhabited central region of Tolkien’s imagined world, Arda, rather than to an entire planet or universe. Many of the best-known places in his fiction, including the Shire, Rivendell, Mordor, Gondor, and Rohan, are located in Middle-earth.
A common mix-up is treating Middle-earth as the name of the whole cosmological setting. Tolkien’s larger mythology includes Arda, the world, and regions such as Valinor, which lies outside Middle-earth. Númenor is also a separate island kingdom, while Beleriand was an earlier western region that was destroyed near the end of the First Age.
The expression was inspired partly by the Old English middangeard, a term connected with the human world.