Ooops, almost all eaten up by greed.
This animated map starts out showing Native American land in 1794. The following year the US and Spain signed the Treaty of San Lorenzo, carving up much of the continent between the two countries. What followed was a century of catastrophes for Native Americans as their land was taken piece by piece. By the time the US passed the Dawes Act in 1887, effectively abolishing tribal self-governance and forcing assimilation, there was very little left.