Rockstar has now officially named six regions in the state of Leonida. That is the whole confirmed list. Everything beyond it, including the map size figures you have probably seen quoted, is community work, and it is worth being clear about which is which.
Vice City is the Miami analogue and the main urban centre, running from the art deco hotels and white sand of Ocean Beach through Little Cuba's panaderias and the Tisha-Wocka flea market out to VC Port.
Leonida Keys is the Florida Keys equivalent, tropical islands strung together by long bridges and coastal highway.
Grassrivers is the Everglades: wetland, waterways and, going by the first trailer, a great deal of wildlife.
Mount Kalaga is the national park in the north, pitched around hunting, fishing and off-road trails.
Port Gellhorn sits on the northwest coast, a faded tourism and trade town now defined by cheap motels, shuttered attractions, liquor stores and truck stops.
Ambrosia is the rural and industrial corner: sugar refineries, biker gangs, old-school American grit.
Now the parts that are not confirmed. The widely repeated claim that the map is roughly twice the size of GTA V, or about 70% bigger, is a community estimate worked out from trailer geography. Rockstar has published no size figure at all. Treat any specific number with suspicion, including that one.
A second state called Gloriana, Georgia-inspired, has been spotted on licence plates. The plates are real and people have read them correctly, but a licence plate is not a playable region, and Rockstar has said nothing about it either way. Interesting, unconfirmed, and quite possibly set dressing.
We have tagged this piece analysis rather than confirmed, because separating the official six from the estimated rest is exactly the judgement call that tag exists for. The individual region entries in the database carry their own labels.