In San Jose, thousands of marchers headed to an evening rally at city hall. In San Francisco, a separate demonstration wrapped up in the afternoon, but not without a bit of trouble.
Three people were attacked and at least two others were arrested. The people assaulted were part of the Minutemen demonstration, a group in favor of Arizona's new immigration law.
They said a large group of immigrants' rights supporters followed them to the BART station on Market Street and started punching and kicking them, and calling them names.
"They said we were racists, and we were against them, and against their town, and against San Francisco," said Parker Wilson with the Bay Area National Anarchists. "What they were saying, they said we need to get out and called us racists, and that we need to go home. And then they just attacked my friends and me."
Those arrested will likely be charged with felony assault and robbery. In the meantime, the rest of the rally got vocal but not physical. Emotions divided the street in front of city hall at Civic Plaza. There were those who support Arizona's immigration law and those who do not.
It was the focus of this May Day, commonly known as "International Workers Day."
"We hope with this march they hear us and get something done," Ramon Hernandez with Liuna Local told ABC7.
Similar rallies took place over the nation Saturday. Immigrants' rights groups hope the Arizona law, which was amended Friday night, will be over turned. The updated version makes racial profiling illegal and an officer can question an immigrant's status only after that person is stopped for another crime and not just because he or she looks suspicious.
"I don't think it's going to stop law enforcement from stopping anybody who looks like an immigrant or has the color brown," said San Francisco resident Erle Woo.
Francisco Perez is in the U.S. illegally and worries that Arizona's law could spread to California.
"I think it should stop completely," he said.
As hundreds of people marched through the Mission with their message, a group of Minutemen waited for them at Civic Center Plaza with different message.
"Immigrants are draining our welfare system. They are draining our school system, the judicial system," Elizabeth Kelly with Golden Gate Minutemen told ABC7.
They support legal immigration.
"Nobody is trying to make this a Nazi police state or anything," said Minutemen member Steve Kemp. "That's not what it's about. What it's about is giving police the authority to be able to question people if they're in this country illegally."
But, Andres Balkan of San Francisco believes, "Minute Men is a neo-Nazi organization."
The Minutemen were dramatically out numbered. Police had to move their opponents back and tighten security. The Minutemen let their signs do the talking.
Police say they had no other problems and no other arrests at the rally.
At the height of the march in San Jose, the stream of people stretched for nearly ten blocks. Most of them were demanding that President Obama tackle immigration reform immediately.
As in other locations, marchers in San Jose said that because of the events in Arizona, the usually-spirited May Day march was bigger and more energized.
"I think yeah, it helped a lot," said Karina Gudino. "Every year, people come but this year, even more I think, because of the Arizona law. They're all against it because it's really a racist law."
"It's just really stupid, what is happening," Vicky Delarenal said. "I think this country is made of immigrants and I think again, we just need to keep fighting for this. That's why I'm here, just to support the people."
In the East Bay, demonstrators at a May Day rally near the Fruitvale BART station said this year's event took on added significance because of the new Arizona law.
"We feel it's going to be racist and discriminatory to the immigrant population, particularly to the Latino population, but actually for all immigrants, because the undocumented population in this country comes from all over the globe," said protestor Lillian Galedo
About 200 demonstrators also marched through Fremont in protest of the illegal immigration crackdown.
People who oppose what is happening in Arizona are angry and loud, but they are in the minority. Polls show the majority of people in America support Arizona's new law.