usa where the population is mainly north american indians?

to tell you the truth I wouldnt think there is any because everyone is everywhere

On the reservations?

from wiki -

In 2006, the U.S. Census Bureau estimated that about 1.0 percent of the U.S. population was of American Indian or Alaska Native descent. This population is unevenly distributed across the country. Below, all 50 states, as well as the District of Columbia and Puerto Rico, are listed by the proportion of residents citing American Indian or Alaska Native ancestry, based on 2006 estimates:

Alaska - 13.1% New Mexico - 9.7% South Dakota - 8.6% Oklahoma - 6.8% Montana - 6.3% North Dakota - 5.2% Arizona - 4.5% Wyoming - 2.2% Oregon - 1.8% Washington - 1.5% Nevada - 1.2% Idaho - 1.1% North Carolina - 1.1% Utah - 1.1% Minnesota - 1.0% Colorado - 0.9% Kansas - 0.9% Nebraska - 0.9% Wisconsin - 0.9% Arkansas - 0.8% California - 0.7% Louisiana - 0.6% Maine - 0.5% Michigan - 0.5% Texas - 0.5% Alabama - 0.4% Mississippi - 0.4% Missouri - 0.4% Rhode Island - 0.4% Vermont - 0.4% Florida - 0.3% Delaware - 0.3% Hawaii - 0.3% Iowa - 0.3% New York - 0.3% South Carolina - 0.3% Tennessee - 0.3% Georgia - 0.2% Virginia - 0.2% Connecticut - 0.2% Illinois - 0.2% Indiana - 0.2% Kentucky - 0.2% Maryland - 0.2% Massachusetts - 0.2% New Hampshire - 0.2% New Jersey - 0.2% Ohio - 0.2% West Virginia - 0.2% Pennsylvania - 0.1% District of Columbia - 0.3% Puerto Rico - 0.2%

So Alaska, New Mexico and then South Dakota…