The two protests come in the aftermath of the events in Charlottesville, Virginia, last week, including when a Nazi-sympathizer drove his auto into a crowd of anti-racism counter-demonstrators, protesting a white supremacist rally, killing one and injuring more than a dozen others.
The almost 500 police officers deployed for crowd control at the event were left dealing with counterprotesters when the participants of the "free speech" rally left the bandstand at the park, according to media reports. Officials said the rallies drew about 40,000 people.
The rally will happen today at noon. Please leave the sticks & stones at home.
The protests appeared to be overwhelmingly peaceful, although CNN said that police arrested eight anti-fascist protesters after briefly clashing with police. Others objected to the event's right-wing speakers and feared that white nationalists might show up anyway.
Samson Racioppi, a congressional candidate originally scheduled to speak at the rally, told WCVB the event "kind of fell apart". Police announced the rally had ended at 1:30 p.m. on Twitter. They chanted anti-Nazi and anti-fascism slogans, and waved signs that said: "Make Nazis Afraid Again", "Love your neighbor", "Resist fascism" and "Hate never made United States great" and burned and stomped on the American flag.
"The groups that are trying to instigate such violence - groups like Identity Evropa, Vanguard [America], the KKK, neo-Nazis - we completely condemn all of that", he said.
"That was never the intention", he said.
Organizer's of Saturday's rally described themselves as a coalition of "libertarians, conservatives, traditionalists, classical liberals, (Donald) Trump supporters or anyone else who enjoys their right to free speech". They also denounced racism, bigotry and violence.
Other demonstrations in solidarity with Charlottesville and against white supremacy were organized by activists in cities across the country, including Portland, Ore., and New Orleans, La.