In J.R.R. Tolkien’s The Lord of the Rings, Mount Doom is located in Mordor.
Mount Doom is the volcanic mountain where the One Ring was forged by Sauron. Its fires are uniquely capable of destroying the Ring, which is why Frodo’s quest ultimately leads into Mordor and toward the volcano’s Cracks of Doom.
Mordor is the harsh southeastern land dominated by Sauron. Mount Doom stands in its northeastern region, near Barad-dûr, and its eruptions and smoke contribute to the threatening landscape described in the novel.
Readers sometimes confuse Mordor with Gondor because the two realms are neighboring powers in the War of the Ring. Gondor is a human kingdom opposing Sauron, while Mordor is Sauron’s stronghold. Rohan is another human kingdom, and Isengard is a separate fortified place in Middle-earth.