Beginning in May, almost 1,000 unmarked graves were found at former residential schools in British Columbia and Saskatchewan that were mainly run by the Catholic Church and funded by the government.
The discovery has sparked a reckoning with Canada's colonial past.
"Bring our children home!" the group of protesters cried, standing on a pedestal where Queen Victoria's statue had previously stood.
Traditionally the first of July - known as Canada Day - is celebrated with backyard barbecues and fireworks much like July 4 in the United States. This year, however, Canadian Prime Minister Justin Trudeau said the day would be "a time for reflection."
A #CancelCanadaDay march in Canada's capital, Ottawa, turned into a sea of orange as thousands rallied wearing orange shirts to honor the victims and survivors of Canada's residential school system.
Orange has come to symbolize the acknowledgment of the victims of the country's residential school system.
Vigils and rallies were also held across other parts of the country.