Zach, who walks with his mother Laurie, has raised about $35,000 since starting the trip last week, USA Today reported Monday.
The boy covers at least 11 miles a day and is collecting letters from children he hopes to give to President Barack Obama in July.
In 2005, when Zach was 7, his family helped him start the Little Red Wagon Foundation to help homeless and underprivileged children. He said he raised about $42,000 in walks from Tampa, Fla., to Tallahassee, Fla., in 2007, and from Tallahassee to Atlanta in 2008.
"These kids don't have a home, they don't have a safe place to sleep at night," Zach said. "They're out on the streets not because they want to be, but because it's out of their control."
An estimated 1.5 million U.S. children are homeless and the problem is worsening with the recession, the National Center on Family Homelessness said.