From Bulbapedia, the community-driven Pokémon encyclopedia.
The Unova League is the regional Pokémon League of the Unova region. The Unova League is composed of eight Unova Gym Leaders and four Unova Elite Four members, along with the Champion. Pokémon Trainers who earn eight Gym Badges by defeating the Gym Leaders of the Unova League qualify to challenge the Elite Four located in the Pokémon League building.
In the anime, it is known as the Vertress Conference.