In all, some 30 tribes or culture groups lived in what is now California, gathered into perhaps six different language family groups. These groups included the early-arriving Hokan family (winding up in the mountainous far north and the Colorado River basin in the south) and the later-arriving Uto-Aztecan of the desert southeast. This cultural diversity was among the densest in North America, and was likely the result of a series of migrations and invasions during the previous 13,000 years, and perhaps even earlier.