Vice City is the neon center of GTA VI's official setting material, but the useful question is what Rockstar has actually shown versus what fans expect from older games.
Rockstar's official GTA VI page places Jason and Lucia on the darkest side of the sunniest place in America and names Vice City, USA. The Leonida page presents Vice City as part of the wider state setting.
That makes Vice City a confirmed anchor, while neighborhood boundaries and full map scale remain best handled as developing information.
Source: Rockstar Games: Grand Theft Auto VI, Rockstar Games: Only in Leonida
Use this page as a clean doorway into Vice City-related articles, map entries, characters, and trailer observations.
References to older Vice City games can be useful context, but GTA VI details should come from GTA VI sources.
Yes. Rockstar's official GTA VI pages name Vice City as part of the setting.
No. Exact boundaries, scale, and every neighborhood should remain unconfirmed until Rockstar publishes more detail.
Only when they are clearly labeled and separated from official information.