The map describes the distribution of ethnic groups located in North America at the time the map was realized. Each group is represented with a  conventional colour and sign. The map doesn't consider the changes European colonization brought. The map is one of the tables made by the TCI Cartographic Office for the Italian Encyclopedia of Giovanni Treccani Institute
<bdi><a href="https://en.wikipedia.org/wiki/en:Renato_Biasutti" class="extiw" title="w:en:Renato Biasutti"><span title="Italian anthropologist and geographer">Renato Biasutti</span></a>
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CC BY-SA 4.0
<bdi><a href="https://en.wikipedia.org/wiki/en:Touring_Club_Italiano" class="extiw" title="w:en:Touring Club Italiano"><span title="large publisher">Touring Club Italiano</span></a>
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