Some spent part of Martin Luther King Jr. Day marching in their own protest, geared toward ending police brutality.
Justice League NYC organized the rally, naming it the "Dream-4-Justice" March.
It began at the corner of 110th Street and Lenox Avenue in Harlem and made its way to the United Nations.
Among the protesters was Joseph Guzman, who was unarmed when he was shot 16 times by police in 2006.
His friend Sean Bell was killed.
"It's more about Sean Bell than anything else. It's more about Eric Garner and Ramarley Graham and other people that have been killed by the police. I'm still here. I'm still alive," Guzman said.
"I feel like I have no choice but to be here right now. It's like, it's 2015 and we're still marching to say that we have the right to live, a right to live the way we want to live, a right to walk down the street and not worry that you could lose your life just because you look suspicious," said protester Kiri Laurelle Davis.
Protesters say they want city and state officials to help end the problem.
They say the state should allow special prosecutors to investigate and prosecute cases of alleged excessive police force.