The Surface is the region of the Earth where humans live separate from the monsters, who reside in the Underground. Both species are separated by the Barrier on Mount Ebott since The War of Humans and Monsters.
Mount Ebott is a mountain on the Surface of the Earth. It is the only known point of entry into the Underground. It is depicted at the beginning of Undertale's intro and in the True Pacifist Ending Credits. Eight Humans fell through the barrier on Mt. Ebott into the Underground.
- "Ebott" spelled backwards is "ttobe", a derivation of Toby. This may be a reference to the game MOTHER 1, which also features a mountain named after its creator, Shigesato Itoi.
- While it is never directly stated where Mount Ebott is, it is likely located somewhere in the United States, as Vegetoid's check text reads "Not monitored by the USDA."