What name is Sauron known by in The Hobbit?

In The Hobbit, Sauron is known as the Necromancer.

The name refers to the mysterious evil presence ruling Dol Guldur, a fortress in southern Mirkwood. Tolkien’s original novel does not initially identify the Necromancer as Sauron by name, allowing the threat to remain a shadowy part of the wider story. The connection becomes explicit in The Lord of the Rings, where the Necromancer is revealed to be Sauron.

This identity links The Hobbit to the history of Middle-earth beyond Bilbo’s immediate adventure. Sauron had lost his physical form after the destruction of Númenor and later re-emerged in Middle-earth, using Dol Guldur as a stronghold while secretly rebuilding his power.

The Necromancer is easy to confuse with other figures in Tolkien’s legendarium. The Mouth of Sauron is a separate servant who appears at the Black Gate, while the Witch-king is the chief of the Nazgûl. “The Dark Lord” is another title for Sauron, but it is not the specific name used for his hidden identity in The Hobbit.