Pokémon Red and Blue are primarily set in the Kanto region.
Kanto is the fictional world explored by the player in the first-generation games. The journey begins in Pallet Town and includes locations such as Viridian City, Pewter City, Cerulean City, and Saffron City. Players travel through the region while challenging eight Gym Leaders and eventually the Elite Four.
The Pokémon setting was inspired partly by real Japanese geography. Kanto is also the name of a real region of Japan surrounding Tokyo, although the game’s Kanto is a fictional adaptation rather than a literal map. Several locations and routes were designed to create a connected adventure across forests, caves, cities, and seas.
Kanto is often confused with Johto because the two regions appear together in Pokémon Gold, Silver, and Crystal. Johto is the setting of the second generation, while Kanto is the original region associated with the 1996 games.