Several male members of the Hopi tribe were held in Alcatraz in San Francisco. Considered to be “hostiles” because they would not conform to the ways of living the government wanted, including the opposition of sending their children to boarding schools, the men were imprisoned.
Source: Craig Glassner. “From Arizona to Alcatraz: Hopi prisoners on Alcatraz.” Found SF. http://www.foundsf.org/index.php?title=FROM_ARIZONA_TO_ALCATRAZ%3A_Hopi_prisoners_on_Alcatraz