The first generation of Pokémon games is set in the Kanto region.
Kanto is the setting of Pokémon Red, Green, Blue, and Yellow. It contains locations such as Pallet Town, Viridian City, Celadon City, and Indigo Plateau. The region is home to the original 151 Pokémon and includes eight Gym Leaders whose badges help the player qualify for the Pokémon League.
Kanto’s geography was inspired largely by Japan’s Kantō region around Tokyo, although the game world uses fictional towns and routes. The name is therefore shared with a real Japanese geographic area, but the Pokémon setting is a stylized fantasy version.
Johto, introduced in Pokémon Gold and Silver, is the neighboring second-generation region. Hoenn followed in Ruby and Sapphire, while Sinnoh appeared in Diamond and Pearl. These regional names are sometimes confused because later games allow players to revisit earlier areas, but Kanto is the first-generation setting.