It is believed that the origin of Native Americans, also referred to as American Indians, go back to late in the last Ice Age.  Native Americans lived throughout North and South America, including Alaska and Hawaii.  At one time, there were over 500 recognized tribes just in North America.    It is estimated that there are still over 1.5 million Native Americans in North America.  The earliest Native American ancestors arrived in North America at least 15,000 years ago.  Some believe it was much earlier than that.  Some of the more well-known tribes in what is now the United States, were the Cherokee, Apache, Comanche, Sioux, Shawnee, Pawnee, Arikara, Cree, and the Iroquois.