Who was living in North America prior to the 9th century?

by coffee_is_my_crack
Reedstilt

There are a host of archaeologically known Native cultures in North America prior to the 9th Century. It might help to narrow the focus of your question down to a specific region or time period. There's a conversation going on now about North American cultures in the 1st Century CE, if you're interested. Also, a couple months ago, I did a series of post discussing the major cultures in Ohio from the Ice Age to the 1600s.