"People have to understand that this is a president who not only is trying to lead a coverup of his own Russia ties, but he has a problem with the truth in general," Andrea Chalupa, an organizer with the March for Truth, told ABC News. "So we're here standing up for the truth."
Timothy Snyder, professor of history at Yale University and the author of "On Tyranny," said he felt he had to take pert in the March for Truth.
"The issue with the Trump Administration is no longer the traditional issue of transparency, it's the issue of fiction," Snyder said. "To say they are not transparent isn't even beginning to characterize it. So for me, the investigation is about Russia, of course, and the myriad connections between Trump's people and Russia, but it's also about fact versus fiction.
"For that reason, we are at a major crossroads about what kind of country we want to be," he added.
For its part, the Trump administration has denied allegations of illegal activity. The Kremlin also has denied the Russian government was behind the cyber campaign to undermine the 2016 election.
Chalupa said organizers began planning the march a few weeks ago and, despite the tight timeframe, felt it was necessary to move forward with Saturday's plans.
Trump has repeatedly said on the campaign trail and while in office he does not have financial interests in Russia.
"March for Truth" organizers said participating organizations include MoveOn.org, Rock The Vote and the Womens March, which organized large-scale protests across the country on the day after Trump's inauguration.
Paola Mendoza, the artistic director of the Womens March, was among those marching in New York on Saturday.
"I firmly believe that the success of the resistance depends on the intersectionality of all our movements," Mendoza told ABC News via email. "The Women's March stands side by side with the March for Truth because when we fight for truth, we are also fighting for the undocumented communities, for women, for our Muslim brothers and sisters and our planet."
Marchers said making their presence felt was important, even if the White House does not acknowledge it.
"The funny thing is about protesting is that it makes you feel better as a person and as a citizen to be with other people who are thinking and acting," Snyder told ABC News. "That's what you get out of protest: you feel like a better American."