The demonstrations - which took place in cities including Los Angeles, Las Vegas, Boston, Washington and Portland, Ore. - were for the most part peaceful. Most of the arrests were for blocking streets, and the traffic disruptions were brief.
Chanting "All day, all week, shut down Wall Street," more than 1,000 protesters gathered near the New York Stock Exchange and sat down in several intersections. Helmeted police officers broke up some of the gatherings, and operations at the stock market were not disrupted.
As darkness fell, a coalition of unions and progressive groups joined Occupy demonstrators in staging rallies at landmark bridges in several U.S. cities to protest joblessness.
In New York, a crowd of several thousand people, led by banner-carrying members of the Service Employees International Union, jammed Manhattan's Foley Square and then marched peacefully across the Brooklyn Bridge on a pedestrian promenade.
As they walked, a powerful light projected the slogan "We are the 99 percent" - a reference to the Americans who aren't super-rich - on the side of a nearby skyscraper. Police officers dressed in wind breakers, rather than riot gear, arrested at least two dozen people who walked out onto the bridges' roadway but otherwise let the marchers pass without incident.
The protests came two days after police raided and demolished the encampment at lower Manhattan's Zuccotti Park that had served as headquarters of the Occupy movement and as demonstrators and union allies tried to regain their momentum.
"This is a critical moment for the movement given what happened the other night," said demonstrator Paul Knick, a software engineer from Montclair, N.J. "It seems like there's a concerted effort to stop the movement, and I'm here to make sure that doesn't happen."
At least 300 people were arrested in New York. Some were bloodied during the arrests. One man was taken into custody for throwing liquid, possibly vinegar, into the faces of several police officers, authorities said. Many demonstrators were carrying vinegar as an antidote for pepper spray.
A police officer, Matthew Walters, needed 20 stitches on his hand after he was hit with a piece of thrown glass, police said.
In Los Angeles, about 500 sympathizers marched downtown between the Bank of America tower and Wells Fargo Plaza, chanting, "Banks got bailed out, we got sold out!" More than two dozen people were arrested.
Police arrested 21 demonstrators in Las Vegas, and 20 were led away in plastic handcuffs in Portland, Ore., for sitting down on a bridge. At least a dozen were arrested in St. Louis in the evening after they sat down cross-legged and locked arms in an attempt to block a bridge over the Mississippi River. More were handcuffed for blocking bridges in Philadelphia and Minneapolis.
In Chicago, hundreds of protesters organized by labor and community groups marched toward the Chicago River. They stopped at the river bridge and shut it down to rush-hour traffic. Police officers scrambled to divert cars and pedestrians. People watched the protests from office windows and bus stops.
In Seattle, hundreds of Occupy Seattle and labor demonstrators shut down the University Bridge as part of a national day of action demanding jobs. Traffic was snarled around Seattle's University District as two rallies marched toward the bridge.
Several of the demonstrations coincided with an event planned months earlier by a coalition of unions and liberal groups, including Moveon.org and the SEIU, in which out-of-work people walked over bridges in several cities to protest high unemployment.
The street demonstrations also marked two months since the Occupy movement sprang to life in New York on Sept. 17. They were planned well before police raided a number of encampments over the past few days but were seen by some activists as a way to demonstrate their resolve in the wake of the crackdown.
Thursday's demonstrations around Wall Street brought taxis and delivery trucks to a halt, but police were largely effective at keeping the protests confined to just a few blocks. Officers allowed Wall Street workers through the barricades, but only after checking their IDs.
Mayor Michael Bloomberg said police had been expecting as many as 10,000 protesters based on what activists had been saying online. But he said there had been "minimal disruption."
"Most protesters have, in all fairness, acted responsibly," he said after visiting an injured police officer in the hospital.
Police Commissioner Raymond Kelly said officers confiscated metal devices that some demonstrators had apparently planned to use to lock themselves into the entrances to Wall Street businesses.
The demonstration that drew thousands of people to Foley Square in the evening was a rarity in the Occupy movement: Union organizers obtained a permit from the city, and speakers were allowed to use a sound system.
Among the demonstrators arrested in New York was a retired Philadelphia police captain, Ray Lewis, who was taken into custody in his dress uniform. Others included actor and director Andre Gregory, who said he hoped the movement would lead to national action on economic injustice.
"It's a possible beginning of something positive," he said.
Some onlookers applauded the demonstrators from open windows. Others yelled, "Get a job!"
"I don't understand their logic," said Adam Lieberman, as he struggled to navigate police barricades on his way to work at JPMorgan Chase. "When you go into business, you go into business to make as much money as you can. And that's what banks do. They're trying to make a profit."
Gene Williams, a bond trader, joked that he was "one of the bad guys" but said he empathized with the demonstrators: "The fact of the matter is, there is a schism between the rich and the poor, and it's getting wider."
The confrontations followed early morning arrests in other cities. In Dallas, police evicted dozens of protesters near City Hall, citing health and safety reasons. Eighteen protesters were arrested. Two demonstrators were arrested and about 20 tents removed at the University of California, Berkeley.
City officials and demonstrators were trying to decide their next step in Philadelphia, where about 100 protesters were under orders to clear out to make way for a long-planned $50 million plaza renovation at City Hall. Union leaders pressed the demonstrators to leave, saying construction jobs were stake.
Associated Press writers Colleen Long, Jennifer Peltz, Meghan Barr in New York contributed to this story.