I probably would when talking about the first people in those specific places. Or the first Europeans in Europe, Africans in Africa, Asians in Asia, Americans i

I probably would when talking about the first people in those specific places. Or the first Europeans in Europe, Africans in Africa, Asians in Asia, Americans in the Americas, etc. "American" also describes the citizens of that one state with the word "America" in the name, which sometimes leads to ambiguity, but not here.