In the week leading up to the rally in D.C., there have been actions across the country. Immigration reform supporters in states like Boston, Miami, Chicago and Los Angeles have been knocking on doors, registering voters and planning "echo" events that will coincide with the gathering in the capital.
The larger rally serves as a way to energize the base working on reform, giving them a chance to meet other people working on the same issue and get a sense of how many other people care about reform.
The Center for Community Change's Matos says that the big rally "creates a sense of community amongst people who have this one shared common interest."
This week's march may not be on the scale of the civil rights protests of 50 years ago, or the immigration-reform marches of 2006, but it could still send a message to policymakers.
For that to happen, though, the groups hosting the event -- labor unions, civil rights, and immigrant rights groups -- will all need to bring large groups of supporters, according to Fisher.
"For them, I would guess the entire intention for them and to show the extent of the coalition involved," she said. "That will play a role in the salience in the issue in terms of how its seen on the Hill."