How do I trace my Native American ancestry professionally?
If your great grandparents are from one of the Five Civilized tribes (Cherokee, Choctaw, Creek, Chickasaw, and Seminole), then you can find then or their parents on the Dawes Rolls (Final Rolls of Citizens and Freedmen of the Five Civilized Tribes, or Dawes Commission of Final Rolls). The rolls are online with some of them being free. You just have to look. If they were not the natives, then you have to do your research through birth, death, probate, and census records. At some point in censuses they did identify Native Americans as a different race.