late edit: DISCLAIMER: The pictured map is not actually a representation of the territories before colonisation. It's a hypothetical map of what countries there might have been had the continent not been colonised, thus all the names and borders are fictional and have never existed.
For good actual maps, check out native-land.ca.
Growing up I recall meeting a lot of people who spoke about their native American heritage, I'd say the majority who made that claim were POC. I wonder if the percentage of people who found out they didn't have any native genetics in them via testing was similar in POC vs white ethnicity's.