Leonida, region by region
The six regions Rockstar has named so far, from Vice City to the swamps. What each one is, who lives there, and what you can do.

Vice City
Coastal Leonida, exact position unconfirmed
Leonida Keys
Offshore island chain, map position unconfirmed
Grassrivers
Leonida wetlands, map position unconfirmed
Ambrosia
Inland Leonida, exact position unconfirmed
Port Gellhorn
Leonida's coast, exact position unconfirmed
Mount Kalaga National Park
Northern Leonida, on the state border (per Rockstar)What is Leonida in GTA 6?
Leonida is the fictional US state where GTA 6 takes place. Rockstar has named six regions so far, from Vice City to the northern wilderness.
Vice City is the urban core, and Rockstar has named four of its areas: Ocean Beach, Little Cuba, the Tisha-Wocka flea market and VC Port. Offshore, the Leonida Keys are sold as relaxed and boozy, with dangerous water just past the beach. Jason Duval lives there, on land owned by smuggler Brian Heder. Grassrivers is an ancient mangrove swamp where the alligators pull in the tourists and stranger things wait out of sight. Port Gellhorn is a former vacation town gone quiet: dead motels, cheap booze, dirt bikes. Ambrosia runs on the Allied Crystal sugar refinery and a local biker gang. At the northern edge, Mount Kalaga National Park offers hunting, fishing and off-road trails, surrounded by backwoods communities that want nothing to do with the government.
How are these region guides built?
From Rockstar's own descriptions, the official trailers and An Extended Look. Nothing from leaks or fan maps.
Each region page states what Rockstar has confirmed, what the footage shows and what is still unannounced, including missions and activities Rockstar has not revealed. Street names and borders floating around online from fan maps stay out until Rockstar confirms them. For the people behind each place, see the GTA 6 characters. For the latest official footage, start with the Extended Look breakdown.