In Manhattan, a group gathered to demonstrate against Trump's immigration policies.
"The main purpose is to tell Donald Trump he can't just deport 11 million undocumented people," Noelle Yasso said. "They're here to stay and we stand in solidarity with them."
Yasso, who said she was an immigration lawyer, said immigrants are terrified, according to CNN.
"They're saying, 'Are we going to be deported tomorrow?' “She said. "People don't know what will happen and they're very scared."
Protesters are upset about Trump's policies on health care, the environment and other issues. Some are questioning the legitimacy of Trump's victory over Hillary Clinton by noting that although he took the Electoral College, Clinton won the popular vote.
Over the weekend, Los Angeles saw anti-Trump protests swell to 8,000 people on Saturday. In New York, thousands peacefully marched two miles on Saturday and gathered outside Trump Tower, the President-elect's home in Manhattan, where they chanted "not my president."
On Sunday, around 100 people peacefully protested in front of the CNN building in Los Angeles, said a member of CNN security. A small protest also took place midday Sunday in Springfield, Massachusetts. Protests also flared in large metropolitan areas including Philadelphia, Oakland, San Francisco, and Chicago.
Since Election Day, many have expressed fears of bigotry and racial violence against minorities, amid incidents of harassment, slurs and hate crimes. In an interview on CBS' "60 Minutes" that aired Sunday night, Trump told his supporters to stop the harassment, and that he would, "bring this country together."
As for anti-Trump protests, he said: "I think it's horrible if that's happening. I think it's built up by the press because, frankly, they'll take every single little incident that they can find in this country, which could've been there before. If I weren't even around doing this, and they'll make into an event because that's the way the press is."