From Bulbapedia, the community-driven Pokémon encyclopedia.
Mt. Spirit (Japanese: 神山 Mt. Kami) is a location exclusive to The Electric Tale of Pikachu manga. It is a tall mountain on the outskirts of Fuchsia City. The flag on its peak is the finishing point for the Fuchsia Free-For-All Race.
Mt. Spirit is covered in steep cliffs and is blanketed in thick fog all year round, making traversing it dangerous.