Mayor Keisha Lance Bottoms announced the curfew during a news conference Saturday evening.
She called it a "very unusual and extreme step" after the violence that rocked Atlanta during Friday night.
Georgia's governor declared a state of emergency early Saturday to activate the state National Guard as violence flared in Atlanta.
In Friday's protests, some demonstrators smashed police cars and spray-painted the iconic logo sign at CNN headquarters downtown. Police say at least three officers were hurt and there were multiple arrests as protesters shot at officers with BB guns and threw bricks, bottles and knives.
Atlanta officials said crews were temporarily unable to reach a fire at a restaurant because of crowds of protesters.
In New York, protesters returned to the streets for a third straight day as Mayor Bill de Blasio pleaded for calm after a demonstration in Brooklyn the previous night descended into chaos that left people bloodied and vehicles burned.
On Saturday, a large crowd marched through Harlem, chanted outside a police precinct and then blocked traffic on the highway along Manhattan's East River.
Demonstrations of several thousand at Union Square and outside Brooklyn's Prospect Park appeared mostly peaceful. Late in the day, protesters in Brooklyn confronted police, who shoved some of the demonstrators and used an irritating chemical spray.
De Blasio expressed solidarity with demonstrators upset over police brutality, but promised an independent review of the Friday night confrontation in which both protesters and police officers engaged in violence.
The mayor said he was upset by videos of the clashes in which "protesters were handled very violently" by police and by reports that a state senator and member of the state Assembly were among the people sprayed with irritating chemicals by officers.
Thousands of demonstrators gathered in downtown Chicago hours after protesters clashed overnight with police.
A crowd converged on Chicago's Loop for Saturday's protest march, during which at least one flag was burned, and some protesters climbed onto a bus and a light pole and surrounded police officers.
Following the overnight clashes with protesters, Chicago officials are urging that demonstrators remain peaceful. Demonstrations are expected throughout the weekend over Floyd's death.
Chicago police Superintendent David Brown says peaceful protests that began Friday afternoon turned more confrontational as the night wore on, resulting in 108 arrests.
Protesters blocked traffic along major streets, threw bottles and other objects at police vehicles and shattered the windows of downtown businesses.
The governor of Ohio is calling out the Ohio National Guard and also asking the highway patrol to help enforce laws in Columbus as the mayors of the state capital and Cleveland both announce 10pm curfews following damage to businesses amid protests over the death in Minneapolis of George Floyd.
Gov. Mike DeWine said Saturday that the vast majority of protesters want "simply to be heard" and focus attention on the death of Floyd, a black man who died after a white officer pressed a knee into his neck.
But the governor adds that sadly the calls for justice and change are "being drowned out by a smaller group of violent individuals." He says that "acts of violence cannot, and will not, be tolerated."
Columbus Mayor Andrew Ginther says he believes racism "is a public health and safety crisis" and he wants to see a more equitable city, but "we are now at a point that we can no longer tell who is protesting for change and an end to racism and who has only chaos and destruction in mind."
Ginther says more than 100 public and private properties in Columbus had been damaged and at least 10 robbed of goods. He says five police officers were injured by thrown bricks or rocks and police vehicles have been set afire.
Texas Gov. Greg Abbott sent more than 1500 state troopers to various Texas cities to help control protests.
Abbott said in a news release Saturday that troopers are being sent to Houston, Dallas, Austin and San Antonio.
Houston Police Chief Art Acevedo says on Twitter that nearly 200 people were arrested Friday and most will be charged with obstructing a roadway as several protesters blocked an interstate and a highway.
Hundreds of protesters gathered in Austin on Saturday outside police headquarters and then marched along Interstate 35.
Floyd died after a Minneapolis police officer pressed his knee into Floyd's neck for several minutes even after he stopped moving and pleading for air.
A television news reporter in Columbia, South Carolina, was injured by rocks thrown during protests outside the city's police headquarters over the death of George Floyd in Minneapolis.
WIS-TV anchor Judi Gatson tweets that reporter Miranda Parnell was being taken to the hospital to be "checked out" after Saturday's incident.
The tweet says Parnell reported that "a person wearing a MAGA hat showed up at the rally, protesters confronted that person & then rocks were thrown."
Several hundred people participated in the demonstration, tearing down the US flag and the South Caroline state flag in front of the police.
The State newspaper reports that some protesters swarmed a police car, breaking its windows.
Police in Las Vegas say 80 protesters were arrested and 12 police officers injured during violence Friday that followed a peaceful protest over the death of George Floyd after he was restrained by Minneapolis police.
According to police, the protest on the Las Vegas Strip began with up to 300 people gathering peacefully. But police say rocks were thrown at police and property was damaged several hours later when officers tried to disperse the crowd as tensions mounted. Police said the arrests were made when protesters refused to disperse.
Police initially said at least 31 people were arrested. Floyd died after a Minneapolis police officer pressed his knee into Floyd's neck for several minutes even after he stopped moving and pleading for air.