In Beringia. The land bridge, which was not so much a bridge as a small continent, between NA and northern Siberia. Lasted for thousands of years until it was drowned by global warming ca. 12,000 (?) BC.
Oppenheimer points out that groups entering before the great Ice Age would have been pushed south by the ice caps, and then as the ice caps melted, would have re-entered the formerly ice-covered areas and repopulated them.
Somehow this article doesn’t seem right.
I have not kept up with the more modern ideas on this. And of course, now with the ability to track DNA it’s completely changed how we can look at it. I find it interesting tho.