Pokémon Red, Green, Blue, and Yellow are set in the fictional region of Kanto.
The player travels through Kanto while collecting Pokémon, earning Gym Badges, challenging the Elite Four, and pursuing the title of Pokémon League Champion. The region contains familiar locations such as Pallet Town, Viridian City, Cerulean City, and Lavender Town.
The name Kanto was not used in the original Japanese first-generation games themselves. It became established in later Pokémon material and was used explicitly in subsequent titles, including Pokémon Gold and Silver, where players can return to the region after exploring Johto.
Kanto is often associated with the real Kantō region of Japan, but the game setting is fictional. The first-generation map also helped establish the series’ formula of routes, towns, caves, forests, and eight Gym Leaders, a structure that later regions adapted.