Rockstar Hasn't posted a GTA 6 map size, and it has not produced a environment map. What it has verified: the game is set within the state of Leonida, its principal city is Vice City, and the point out has 6 named areas, Every with its own official description on https://waylonoljmw.ktwiki.com/2428589/little_known_facts_about_gta_6_map_size_vs_rdr2