No shootings, burglaries, lootings or property damage were reported, and no one was injured, police said.
Police made arrests after protesters blocked a traffic lane on West Florissant Avenue. Officers with bullhorns directed protesters to clear the roadway, and others in riot gear forced people out of the street. Some demonstrators threw rocks and frozen water bottles at officers, and one St. Louis County police officer was hit in the chest with a small chunk of concrete but was not injured because of his protective vest, police said.
St. Louis County Police Chief Jon Belmar spoke with protest leaders several times throughout the night, hoping to deescalate the tension, police said.
Earlier in the evening a crowd of hundreds gathered, holding signs and chanting as part of a demonstration.
St. Louis County remains under a state of emergency, which was declared Monday. The state of emergency follows an outbreak of violence in Ferguson, including a police-involved shooting Sunday night that left a man in critical condition.
Two teenagers were also shot early Monday as they walked on a sidewalk near a memorial for Brown. The teens were both hospitalized with non-life-threatening injuries, police said.
The death of Brown sparked protests and touched off the national "Black Lives Matter" movement.
The Associated Press contributed to this report.