From Bulbapedia, the community-driven Pokémon encyclopedia.
Silver Town (Japanese: シロガネタウン Shirogane Town) is an anime-exclusive town at the base of Mt. Silver. Its main attraction is the annual Silver Conference.
At least 30 inhabitants are said to be living in the town. There is an Athlete's Village which consists of a huge Pokémon Center where trainers participating in the tournament stay. There is a stadium located nearby where the Silver Conference matches take place.
Ash, along with his friends reached Silver Town in A Claim to Flame! to participate in the Silver Conference.