From Bulbapedia, the community-driven Pokémon encyclopedia.

Stone Town is a small village in Kanto located in between the Safari Zone and Cinnabar Island. It made its only anime appearance in The Battling Eevee Brothers.

The one part of Stone Town that sets it apart from other places is the fact that it's a popular place to evolve Pokémon with stones. When Ash and his friends arrived in Stone Town, they came across a party where trainers from all around were evolving their Pokémon. The party was actually meant for Mikey, the youngest of the Eevee brothers, who had yet to evolve his Eevee. In the end, he decided to keep it the way it was, and the brothers eventually decided it was okay for him to do that.

Mikey's older brothers also tried to convince Brock and Ash to evolve their Vulpix and Pikachu, respectively. Both declined, saying they couldn't force their Pokémon to evolve.

Anime- and Special-exclusive locations in Kanto

A.J.'s Gym | Cerise Island | Chrysanthemum Island | Camomile Island | Crimson City | Dark City | Fennel Valley | Frodomar City | Gaiva Dam | Gardenia Town | Grandpa Canyon Gringey City | Hidden Village | HopHopHop Town | The House of Imite | Kas Gym | Leaf Forest | Maiden's Peak | Mossgreen Village | Mulberry Town | Mt. Hideaway Neon Town | New Island | Pokémon Land | Pokémon Tech | Porta Vista | Potpourri Island | Rifure Village | Rota | Sayda Island | Scissor Street | Silver Town | Stone Town Sunny Town | Terracotta Town | Tree of Beginning | Wisteria Town | Yas Gym