"We will have a lot of flags, our signs and a bullhorn," said Jeff Hall, Southwest States regional director of the organization.
"We're going to be heard and let it be known we're against illegal immigration ... we believe in free speech. We're going to make our voices heard."
Hall, who expects between 30 and 40 people from his group at the rally, said the exact location will probably be announced on Monday.
The rally is in response to Claremont Colleges students who have protested in favor of "open borders," Hall said. "Our guys from Claremont wanted a voice."
City Manager Jeff Parker said a counter rally, by a group called Claremont for Peace, would be held at the same time at Memorial Park, 840 N. Indian Hill Blvd.
"It seems to be more people talking about this Claremont for Peace rally that's out there," Parker said, adding he did not know the group's organizers.
The neo-Nazi group does not have to have a permit for its rally unless it were to block the sidewalk or hold a parade, Parker said.
The Claremont Police Department has prepared a tactical plan and is in contact with the organizers, city officials said, and has scheduled additional officers with neighboring police agencies assisting if necessary.
Parker said the city wants to protect the First Amendment rights of all involved.
"The biggest fear we have is we want to have whatever it is be peaceful. We don't want people to incite anything, no matter who it is."
Hall called his organization "the largest white Nationalist Socialist group in America. We're the only National Socialist group in America that protects the border."
Hall said he wants "a white nation that doesn't have multiculturalism forced on them."
According to the group's website, its "core beliefs include defending the rights of white people everywhere, preservation of our European culture and heritage, strengthening family values, economic self-sufficiency, and reform of illegal immigration policies, immediate withdrawal of our national military from an illegal Middle Eastern occupation and promotion of white separation."
Raymond Herrera, founder and president of the Claremont-based anti-illegal immigration group We the People, California's Crusader, said he opposed the neo-Nazi rally.
"We do not align ourself with groups that are neo-Nazi or La Raza or any group that's racist," Herrera said. "As far as our opinion of illegal aliens or immigrants, we don't stand with them. We have our own opinion. We uphold the rule of law."
Herrera said he personally "detests" racist organizations, whether neo-Nazi, Ku Klux Klan or any other.
"We will never sit in the same room as any of them. We are all Americans, and ethnicity plays second fiddle."
Herrera added that "We the People will fight the battle for America in a moral and political manner."
Nazi ties and racial incidents are not unheard of in Claremont.
Claremont resident Richard Bunck admitted to involvement in a 1970s Nazi Party as he unsuccessfully ran for a Claremont Unified School District board position in August 1999. Earlier that year, he had run unsuccessfully for a Claremont City Council seat.
In the same year, Bunck's friend Hale McGee ran unsuccessfully for a Claremont school board seat. El Monte police intelligence files from the 1970s indicated McGee had run a Nazi-affiliated bookstore. The files also showed that Bunck was then an active member of a Nazi splinter group.
The fatal January 1999 officer-involved shooting of Irvin Landrum Jr., an 18-year-old black motorist, polarized Claremont as two officers involved in the incident were later named city employees of the year, and the shooting led to charges of institutionalized racism.
In the wake of that incident, the Claremont City Council formed the Police Commission afterward to look at police bias.
In December 2006, three Inland Valley men were convicted of hate crime charges, assault and attempted murder for the stabbing and beating of a black man.
The men, who were traveling to Westwood for a white supremacist rally, had stopped at a shopping center at Indian Hill Boulevard and San Jose Avenue in Claremont when they encountered the man and a friend, insulted him with racial epithets and then fought, authorities said.
Staff writer David Allen contributed to this report.