Mount Kalaga National Park
Lakes, rivers and high ground with dangerous wildlife. The closest thing Leonida has to Red Dead's Ambarino.
Mount Kalaga National Park covers the remote high ground: lakes, rivers, forest and wildlife that is genuinely dangerous.
It is the region most often compared to Ambarino, which is to say it is probably where the exploration, the fishing and the hidden things live rather than the missions.
A mountain in Florida
This is the one region that is not a straight translation of somewhere real, because Florida does not have mountains. The highest natural point in the state is Britton Hill in the panhandle at about 345 feet, which is the lowest state high point in the country. There is no Florida equivalent of a mountain national park.
So Rockstar has invented one, and it is worth being clear that it has, because a lot of writing about this region assumes a real-world counterpart that does not exist. The nearest genuine equivalents are the forested rolling country of the panhandle and north Florida, which look nothing like what the name suggests.
Why invent it
Elevation does things a flat map cannot. It gives you views, which matter enormously for a game people screenshot. It gives you roads with switchbacks, which drive differently from a grid or a causeway. It gives you places that are difficult to reach, which is where collectibles and secrets go. And it gives the map somewhere genuinely cold-looking to balance six other regions that are all warm.
Red Dead Redemption 2 opened in Ambarino and used it as a statement about scale before dropping the player into farmland. Leonida having its own version suggests Rockstar wanted that register available.
What is likely here
Fishing, wildlife and exploration have all been referenced in coverage of the park. Given the studio's recent history, expect the systems rather than the missions: things you do because the place is there rather than because somebody phoned you.
What is not known
Rockstar has not detailed the park, has not confirmed fishing as a system, and has not shown extended footage of the region. Its size relative to Grassrivers is unknown, and no elevation figure has been given.