As in other regions, the Kanto region holds a number of Gyms located throughout the area. In the Generation I games and their remakes there are a total of eight Gyms. In the Pokémon Anime, the main character Ash, battled at eight Gyms as well. However, as seen with several characters' Badges, there were other unidentified Gyms that were not shown.
The Cinnabar Island Gym leader is Blaine, he gives out the Volcano Badge, he uses Fire-type Pokémon. In Gold, Silver and Crystal, the volcano on Cinnabar Island was destroyed say for the Pokémon Center so Blaine had to relocate to the Seafoam Islands. In HeartGold and SoulSilver his Gym was redesigned and had trainers.
Viridian City's Gym Leader, in Blue, Red, And Yellow, is, somehow, the Team Rocket leader Giovanni, who uses Ground-type Pokémon. In Heartgold, Soulsilver, Gold, Silver and Crystal versions; the leader is Blue who uses all types of Pokémon.