I've read a book called 1491 and they suggest that the population of the Americas was around 100-150 million. Hardly sparsely populated.
Except that that
is very sparsely populated. If something is very sparsely populated, it means its population is not very large considering its area. Even today, the United States is pretty sparsely populated when compared to a lot of countries. There are something like 40 people per km2 in USA (excluding Alaska), compared to over 500 in England.
The Americas span 42,549,000 km2. 150,000,000 divided by 42,549,000 gives us 3.5. That is 3.5 people per square kilometre- a lower population density than modern Canada (A country the size of China with a population lower than some Chinese cities).
For comparison, according to
this Wikipedia article, England and Wales had 3.6 million people in the year 1500. England and Wales combined have a land area of 131,398 km2. 3,600,000 divided by 131,398= 27. So, when there were 3.5 people per km2 in the Americas, there were 27 in England and Wales. According to
this just a century later the area that is now modern India was inhabited by 100 million people, but India is only 3,287,263 km2, compared to the 42,549,000 km2 of the Americas.
...You're aware that's half the current population of the United States alone spread across two continents, and much of the land between the Appalachians and the Rockies is still sparsely populated by Old World standards?
Exactly.
Edit: Just noticed the moderator instruction to end this conversation- sorry.