Joel Robinson is spearheading efforts to protect the 400 acres between Irvine Regional Park and Peters Canyon Regional Park in Orange.
"These are two of our busiest parks in our entire Orange County," said Robinson.
He's a part of the No Orange Heights campaign, which looks to stop the development of the land into residential housing.
"We can't afford to lose the cultural history," said Robinson. "We can't afford to lose the natural history of this area."
Irvine Company was approved to build the Orange Heights community in 2005, which included 4,100 homes between East Orange and Irvine Park.
In 2014, they reduced the plan and donated the majority of the land to the county.
"After decades of community collaboration, we voluntarily donated 90% of our Orange Heights property as public open space and are now completing a master plan for new homes on a small portion of the land identified by environmentalists and our planners as the ideal place for a new community," said Irvine Company.
The current Orange Heights plan would create 1,180 homes.
Robinson said that threatens wildlife and assessments of the impacts to the community need to be reviewed.
"This is basically where development stops and to have this sprawl, blatant sprawl, based on out-of-date documents to go forward is just ... doesn't make sense," he said.
The No Orange Heights Campaign is urging people to sign its Change.org petition.
They're also asking people to reach out to the city of Orange's mayor and city council requesting a new environmental impact report.