LOS ANGELES -- Thousands of immigration-reform activists are taking to the streets around the United States.

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Demonstrators are demanding a path to citizenship for an estimated 12 million immigrants. They also oppose the more than 700 miles of new walls and fences being built along the U.S.-Mexico border. Some also favor a new sanctuary movement that would allow churches to shelter illegal immigrants faced with deportation.

Democratic Party Chairman Howard Dean told a gathering of activists in Miami that an immigration bill currently before Congress is "insane" for requiring many of the nation's 12 million illegal immigrants to return home before applying for citizenship .

Approximately 2,000 people wearing white and carrying or draped in American flags marched in the streets of Phoenix as a mariachi band played. They carried signs saying "Stop the roundups," and, "The sleeping giant woke up forever."

Roberto Organo, an illegal immigrant who said he crossed the border from Mexico 15 years ago, carried a sign that read, "I have a dream. Peace for all my people."

"We are not criminals," Organo said. "We are looking for work to support our families. It's OK for government to enforce the law but they have to give us a chance."

"We want just reform," said Mayela Ruiz, another illegal immigrant. "I've been here 15 years. I've worked hard, paid my taxes. I've had no problems with the law and I'm afraid to leave my house. I want a law that would allow me to work and live in freedom but not like a slave."

California officials are bracing for more than 100,000 protesters in the Civic Center and MacArthur Park areas of Los Angeles. Due to the planned events, 60 bus routes will be rerouted and parts of 17 downtown streets will be closed for much of the day. Some groups are calling for an end to police sweeps of illegal immigrants, while others oppose guest-worker programs and support making it easier for illegal immigrants to become legal. Los Angeles Mayor Antonio Villaraigosa and Cardinal Roger Mahony, head of the Roman Catholic Archdiocese of Los Angeles, both strong immigrant supporters, urged students to stay in school.

For the second year, thousands of immigrant rights supporters are expected to take to the streets of Denver. Supporters expect participants from from Fort Collins, Colorado Springs and beyond to converge on Colorado's capital.

Georgia immigrant rights groups seem to be sitting out the nationwide marches and protests. No local group has announced any boycott or march today. And some of the organizers from last year say that's because immigrants in Georgia are afraid of the upcoming implementation of last year's Senate Bill 529. That set of measures, most of which go into effect in July, was considered the country's toughest law targeting illegal immigrants when Georgia lawmakers passed it last spring.

In Illinois, "Our No. 1 goal is public safety, and we encourage everyone while exercising their First Amendment rights to be respectful of others without interfering with their rights of movement," said Chicago Police Deputy Superintendent Charles Williams. Hundreds of Chicago police, state and county officers and federal agents are lining the march route to Grant Park, TV station WMAQ reported. Protesters chanted slogans in favor of immigration reform, while others beat drums. Signs proclaimed, "Our hard work feeds your families," and, "We are not criminals."

Texas immigration activists are expected to take to the streets of El Paso on Tuesday. Last year's May 1 protest at the Chamizal National Monument caused downtown El Paso to shut down, as many protesters boycotted American goods. This year, protesters will meet near the Santa Fe bridge and cross the Rio Grande at the Juarez monument.

Hispanic rights groups in the Maryland region are organizing a work stoppage to show that they play an important role in the economy. Some leaders in the Hispanic business community aren't supporting the demonstrators. The president and CEO of the Mid-Atlantic Hispanic Chamber of Commerce, Jorge Ribas, said the boycott proves nothing and may have a negative impact on the debate over immigration reform. Ribas also said the immigrant population is so small in Maryland, the boycott might go unnoticed.