Demonstrators march through Times Square in support of special counsel Robert Mueller.
Demonstrators in New York City stayed up late into the night.
Mueller is believed have begun writing a final report on Russia's interference in the 2016 US presidential election.
Demonstrators also gathered in front of the White House in Washington D.C.
Some of the demonstration's organizers said that acting Attorney General Matthew Whitaker's appointment was a "deliberate attempt to obstruct the special counsel's investigation."
Some of the slogans they chanted included "Hands off Mueller" and "Nobody’s above the law."
Similar rallies were being held across the country.
Protestors cheer during a demonstration in support of Mueller in Las Vegas, Nevada.
People gathered in front of City Hall to take part in the protest in Los Angeles, California.
