Description
This is/was a part of a scenario of sort of Lusophone "Hail Brittania", where this brazil would be divided in 5 vice royalties that are equal to mainland portugal, or angola, or Ceilão
(note ignore the santo andré, it's supposed to be são paulo)
Click to expand...
If you ask about why the population is so high despite being half the size of brazil, well there's a rather interesting fact, the amazon and the rio grande do sul were actually useless during colonial brazil! The Amazon would still be useless and underpopulated (except by indians and some poor metis, sadly many were killed during the cabanagem revolt) until the rubber boom, and the rio grande do sul was virtually empty until the second half of the 18th century, and even during the late colonial brazil was only useful as a cattle raising region. Of course later it would be the place of important german and italian migration, and would become one of the wealthiest region of brazil.... But colonial brazil wouldn't be any less populated by 1820 than IRL by any signficant amount. The Mato Grosso was also very underpopulated and was still a savage, untammed places by the late 19th century.
But actually, quoting wikipedia , only about 20% of the current population comes from 19th/20th century immigration (not counting slave trade...), and anyway most of those who came there went to plantations in sao paulo, rio grande do sul or interior parana were only secondary destinations, and most of the migration to the amazon was intra-brazil, few migrants (only some dozen thousands IIRC) went directly there IRL. And then i added the fact that i made it somewhat wealthier (although still with large inequalities... slavery was still a reality as IRL) and more interconnected with the portuguese empire (which is larger there) there is a continued sustained immigration from africa and the indian subcontinent and europe in the 20th century, hence why it's even more populated than IRL (although lower poverty rate means the natural growth during the late 20th century would be lower, but it's a good thing, the country's more educated and favelas are inexistent).
(French) Antarctica is an interesting bit, it was colonized by the french and served as a dumping ground for Hugenots, but between the very early colonization (late 16th century, british continental north america wasn't even a thing), the disease free and fertile reigon and the large numbers of (not all volunteers...) settlers, its population very quickly grew to several millions and expended through the southern cone by the 18th century, it unilateraly declared independance from france in the 1710s, and were at this point already a few millions, France couldn't do anything to keep them... Then they evolved very particularly, i imagine them as "French Boers", after all the Cape colony had strong hugenot immigration (at some point they outnumbered dutch), they got along well with the local calvinists and this is why many afrikaners have french surnames. They quickly outnumbered and killed/displaced all natives from the entire southern cone, but at the same time were very rural, religious and also anti-immigration. The result is that today they are nearly 200 millions in a quite isolationist country, the largest food producer, although not quite as much an industrial power as its population and development level may make you think (still a major power), and minorities, either migrants or natives are very few, the vast majority of the population being able to trace their ancestry entirely to 16th/17th century settlers.
While most who went south stayed in the country, some french speaking hugenots/voyageurs went north and mixed with local natives, particularly guaranis and ofayés, these métis were creole speaking and reformed, but the antarcticans didn't consider them their countrymen... eventually they decided to split and make their own state in the IRL mato grosso and Paraguay, their presence prevented, or at least detered the Brazilians/Portuguese from going into the Mato Grosso.
Spanish New Castille was for most of the 17/18th century limited to its capital, Navalilla, at the mouth of the Amazon, along with some prospectors who heard about supposed gold and riches on the Marajo island, although it turned out to be just isolated relics of the Marajoara culture, and the place stayed a backwater for the prospectors too poor to leave for nearly two centuries, the poverty of the colony means that Navalilla, the only true city, decided to stay with Spain when other colonies decided to become independant in the mid 19th century, but it wouldn't be developped until the rubber rush in the late 19th century, hundred of thousands of Spaniards came to the colony, which was for a short time the first destination for spanish migrants, cities appeared nearly overnight along the amazon, much to the dismay of the natives who suddenly had to fight for their survival. Eventually by the early to mid 20th century, when the revenue of natural rubber started to drop and spain increased its taxation, it decided to break away, but it hasn't done too well since, and the natives who live outside of the main cities live in some of the poorest conditions on the whole continent.