Possibly although at some point someone had to be the first humans in an area
> Possibly
Definitely.
> at some point someone had to be the first humans in an area
Yes, and we know who they were. Hundreds of different tribes, spanning from coast to coast.
They came during the last Ice Age, crossing over the Bering Straight which was solid ground at that time.
The way American settlers treated the native peoples is not something that can just be "possibly"-d away.
Anyway the idea of land "ownership" is kind of stupid in the first place. You can't "own" land, you can just possess it under the rules of some kind of system of power.