Navajo voters are headed to the polls to narrow a record field of 18 presidential candidates.
More than 93,000 Navajos are registered to vote in Tuesday's primary. The top two candidates move on to the November general election.
Candidates have spent the last couple of days campaigning on the radio, in tribal communities and on social media.
The field includes seasoned politicians who tout experience and newcomers who are challenging the status quo.
The reservation is the country's largest at 27,000 square miles in Arizona, New Mexico and Utah. The unemployment rate hovers around 50 percent, and many Navajos still live without running water and electricity.
Current Navajo President Russell Begaye is seeking re-election.
Navajos also will vote for candidates for legislative seats.
Polls close at 7 p.m. MDT.