From Bulbapedia, the community-driven Pokémon encyclopedia.
Sable City (Japanese: サビシティ Sabi City) is a small anime-exclusive town located in Kanto. It is located very close to Pewter City. It made its only anime appearance in The Ole' Berate and Switch!.
Ash and his friends pass by this city on their way to Pewter City and the Battle Pyramid.
Places of interest
One-day Battle Tournament
In The Ole' Berate and Switch!, Sable City held a one-day Pokémon Tournament, in which Ash entered to train for his upcoming battle with Pyramid King Brandon. Many people from the city entered the event to battle their Pokémon. It was actually ever only a scheme by Butch and Cassidy to steal the small city's Pokémon and give them to the Boss.
The One-day Battle Tournament was held in a big stadium with state-of-the-art Pokémon healing center. Only one battle was ever seen in the stadium, which was Howie and his Pinsir vs. Ash and his Corphish. This is also the place where Team Rocket get back together.