Crimson City
From Bulbapedia, the community-driven Pokémon encyclopedia.
Crimson City is an anime-exclusive location believed to be in Kanto. It has not been visited by Ash and his friends, but is mentioned in the episode The Fourth Round Rumble at the Indigo Plateau. A Trainer at the Grass Field which Ash had to battle, Jeanette Fisher, comes from Crimson City.

