If the three-wave theory of the peopling of the Americas is correct, the answer to this is that the last wave of migrants to the Americas consisted of a group now called the Eskaleut. These people came to the Americas only about 7,000 years ago, some 5,000 years or so after the second of the three waves.
The Eskaleut are the wave that did the least in terms of dispersing across the Americas. In North America, their descendants live only along the very northern edges of Alaska and Canada.
Once again, this theory remains controversial and is not accepted by all scholars.