Instead of concentrating on large May Day demonstrations, organisers cited by the New York Times, said they had chosen to hold smaller actions in more than 100 cities nationwide, to draw more local supporters.
There were marches in Birmingham, Alabama, and Milwaukee, and a rally on the steps of the state Capitol in Denver, the influential US daily reported.
In downtown Los Angeles, where several thousand people marched, vendors sold the flags of many nations, but most marchers preferred American flags.
In Tucson, 250 people turned out for a morning march in desert heat. Marchers said the prospect of action in Washington had created an upbeat mood.
On the steps of the Capital in Salem, Oregon, Governor John Kitzhaber, a Democrat, received cheers from demonstrators when he signed a bill allowing immigrants in the country illegally to obtain special driver's licenses in the state.
In Chicago, hundreds of protesters marched through downtown streets, some dressed in stars and stripes and others waving Mexican flags, holding signs that read "Stop Deportations" and "Legalization for All," the Times said.
Addressing the Chicago crowd was Democrat Senator Richard J. Durbin, one of the authors of the immigration bill prepared by the bipartisan Senate Gang of Eight - four Democrats and four Republicans-appealed for unity. "We have the best chance we've had in 25 years to pass comprehensive immigration reform this year in Washington, DC," he was quoted as saying.
"The big strategy is to point the people power of the movement towards getting Congress to finish the job in 2013," Deepak Bhargava, executive director of the Center for Community Change, one of the main organisers of Wednesday's events, was quoted as saying by the Times.
Bhargava said immigration groups would focus their efforts on specific lawmakers who could influence the outcome of the vote.
People who attended the events Wednesday were asked to send e-mails and make calls to the lawmakers on the spot.