From the Introduction: "The U.S. Election Assistance Commission (EAC) is an independent, bipartisan commission charged with helping to improve American elections. One of the EAC's top priorities is serving as a national clearinghouse of information on election administration so that all eligible Americans can fully participate in elections. According to the U.S. Census Bureau, the current total population of Native American persons in the United States is over 9.7 million. Native Americans are diverse Indigenous peoples of the United States, with over 574 unique federally recognized tribal governments-- this number changes annually as tribes gain or lose federal recognition. Federally recognized tribes are entities recognized as having tribal sovereignty and are entitled to certain protections because of their relationship to the United States. Tribes determine their own governance structures and write their laws except where a treaty or legal decision applies. Each tribal government has a formal nation-to-nation relationship with the United States government. Native Americans are both citizens of their tribes and citizens of the United States. Tribal citizens are guaranteed the same full U.S. and state constitutional rights and protections as every other citizen, including voting rights, whether they live on or off tribal lands. [...] Ever since the United States formally became a nation, Native Americans have faced unique barriers to obtaining full citizenship and voting rights. This document details some of the mitigation measures jurisdictions have implemented when administering non-tribal elections in areas where federally recognized tribal governments are located."
U.S. Election Assistance Commission: https://www.eac.gov/