About a dozen people, half with masks, gathered after noon Friday outside the state Capitol, waiving signs that read "Solidarity with Humanity" and "Capitalism is Non-Essential."
Mike Davis, one of the organizers, said the group gathered because of May Day and recent protests against the economic shutdown due to the novel coronavirus.
"The Trump supporters who've been coming out, they don't speak for us," Davis said. "We're the real protesters, against corporate greed and the exploitation of Mother Earth."
Davis, a landscaper and musician, said the aim was raising awareness of imprisoned South Dakota indigenous rights activist Leonard Peltier.
Peltier, a member of the American Indian Movement, was convicted in 1977 for killing two FBI agents in a shootout. Human rights advocates have raised doubts about whether he was guilty and whether he received a fair trial.