Pokémon Red, Blue, and Yellow are set in the fictional region of Kanto.
Kanto is the setting of the first-generation Pokémon games and contains the towns, routes, caves, seas, and Gyms that players visit while pursuing the Pokémon League title. Its geography is inspired by Japan’s real Kanto region.
The game map includes locations such as Pallet Town, Viridian City, Cerulean City, and Saffron City. Players also travel through landmarks including Viridian Forest, Mt. Moon, and the Safari Zone.
Kanto is sometimes confused with Johto because the two regions are connected in Pokémon Gold, Silver, and Crystal. Kanto, however, is the original region and is the only main region explored in the first-generation games.