But police shut down a protest in Portland, Oregon, that they said had become a riot, after marchers began throwing smoke bombs and other items at officers. Police said they made more than two dozen arrests as a group of anarchists wearing black bandanas and ski masks grew unruly, reportedly breaking windows at businesses, setting fires on downtown streets and damaging a police car.
Five people in Seattle were arrested, one for hurling a rock as pro- and anti-Trump demonstrators faced off.
In the Washington state capital of Olympia, police ordered protesters to disperse, calling them "members of a mob" as some threw bottles, used pepper spray and fired marbles from slingshots at officers. Objects struck nine officers and nine people were arrested, according to Olympia Police Chief Ronnie Roberts.
In Oakland, California, at least four were arrested after creating a human chain to block a county building where demonstrators demanded that county law enforcement refuse to collaborate with federal immigration agents.
Despite the West Coast clashes, most nationwide protests were peaceful as immigrants, union members and their allies staged a series of strikes, boycotts and marches to highlight the contributions of immigrants in the United States.
"It is sad to see that now being an immigrant is equivalent to almost being a criminal," said Mary Quezada, a 58-year-old North Carolina woman who joined those marching on Washington.
She offered a pointed message to Trump: "Stop bullying immigrants."
May 1 is International Workers' Day and protesters from the Philippines to Paris celebrated by demanding better working conditions. But the widespread protests in the United States were aimed directly at the new president.
Trump, in his first 100 days, has intensified immigration enforcement, including executive orders for a wall along the U.S.-Mexico border and a ban on travelers from six predominantly Muslim countries.