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Eastern Foothills of Orange County. Access through scheduled events only.

Acres: 22,500

Printable Map

Park Hours: Access only through scheduled programs or Wilderness Access Days.

Black Star Canyon Road is always open for public use and access to Cleveland National Forest.

Parking: Free

Dogs: Not permitted, except on Black Star Canyon Road.

                                                                                                  Activities and Programs

The Irvine Ranch Open Space consists of protected wildlands, including six nature preserves. OC Parks stewards these special lands in close coordination with the Irvine Ranch Conservancy as land management contractor and The Nature Conservancy, a conservation organization. Various educational and recreational opportunities are available through regularly scheduled programs. Other uses are prohibited as specified by deed restrictions and conservation easements. We invite you to visit and select from the many free activities offered.

Trails: hiking, biking and equestrian activities through regularly scheduled programs

Monthly self-guided Wilderness Access Days scheduled

Named a State and a National Natural Landmark

Volunteer opportunities


On June 29, 2010, the Orange County Board of Supervisors voted to accept a donation of 20,000 acres from the Irvine Company to the County for preservation and guided recreation. Additional acreage was donated in late 2014. The historic Irvine Ranch’s origins date back to the 1830s as a Mexican Land Grant to Don Jose Andres Sepulveda. In 1876, James Irvine bought out his partners on the land. During this time, he successfully fought to secure the borders from squatters and the Southern Pacific Railroad. From 1876 to 2010, the historic Irvine Ranch was used for ranching and mining operations, and evidence of this can still be observed. Based on evaluations and the recommendations of the Science Advisory Committee of the National Park Service, the National Park Service Advisory Board, and the National Park Service director, the Secretary of the Interior designated the Irvine Ranch National Natural Landmark in 2006. A similar objective review led to the designation as a California Natural Landmark on Earth Day 2008 by the California State Parks director.