Irvine Ranch Open Space

These 25,000 acres in the Eastern Foothills of Orange County were once part of the historic Irvine Ranch. Now the park is a designated State and National Natural Landmark.

Park Information

13333 Black Star Canyon, Silverado, CA.

This area is accessible through regularly scheduled programs with advance registration only.

OC Parks and Irvine Ranch Conservancy staff and experts conduct interpretive programs year-round, including guided hikes, mountain bike treks, and kid-friendly nature walks.

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Trail Map
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714-973-6696

25k

acres of the Reserve's protected land

different nature preserves are part of this space

20-40

million-year-old red rock formations

More about Irvine Ranch Open Space

This sprawling natural space—which covers a large portion of the Historic Irvine Ranch—boasts lush woodlands, craggy canyons, and magnificent ancient rock formations, plus all of the animal species that make up Irvine Ranch Open Space’s flourishing ecosystem. This area of the NROC is only accessible via docent-led tours and monthly Wilderness Access Days. Sign up to experience this protected wildland and its six nature preserves, including:

Black Star Canyon Wilderness Park: Red rock cliffs climb to epic heights in this area of the Santa Ana Mountains that also borders the backcountry of Cleveland National Forest. Some areas overlook Irvine Lake, which sweetens the view.

Gypsum Canyon Wilderness: Prehistoric cobble and sandstone bluffs, plus two panoramic overlooks, are the hallmarks of this 500-acre property. It’s also stacked with sycamore trees and old-oak meadows, and it pops with the colors of California poppies in spring.

Fremont Canyon Nature Preserve: Massive rock formations are just one of the reasons this park is known as “the Yosemite of Orange County.” It also acts as a corridor for wildlife traveling from Irvine Lake to the Santa Ana Mountains.

Limestone Canyon Nature Preserve: The crown jewel of this lush, spectacular park is a unique rock formation known as the Sinks—Orange County’s version of Arizona’s Grand Canyon, just on a less-massive scale. (The awe, however, remains outsized.)

Red Rock Wilderness: Immerse yourself in these ancient lands on the Sespe formation—an area that’s 20 to 40 million years old and full of fossils. Hikers, mountain bikers, and horseback riders are rewarded with a stunning overlook offering a 360-degree view.

Saddleback Wilderness: Serving up sweeping views from the mountains to the sea, this area of the Irvine Ranch Open Space is a sight-seeker’s dream.

Choose your own adventure: Irvine Ranch Open Space has got the nature. How do you want to enjoy it?

Get wild! But do it respectfully.

: Expect the unexpected on your adventure. Tell a friend or family member where you are going and what time you plan to return, keep an eye on local weather reports, bring plenty of water, and carry emergency essentials with you. Some areas of the NROC do not have cell service, so you may not be able to rely on your smartphone for routing or communication. It’s smart to have a warm layer, rain jacket, and headlamp in your pack, along with means to stay hydrated and fueled beyond what you expect you’ll need, especially in the more remote areas of the Reserve.
: Each park within the NROC has its own activities, hours, and guidelines, all rooted in respect for the land. Before you visit, check out their site so there are no surprises.
: Nurturing the beauty of this nature is a communal effort—love your wild by taking nothing from the Reserve and leave no trace behind.
: You are bound to see some exciting wildlife on the Reserve, and we do mean wild. Respecting the animals’ space will ensure your safety and theirs.
: Though encountering them is rare, some larger or venomous animals could be threatening—the best thing to do is stay calm and be prepared. If you encounter a mountain lion, maintain eye contact, speak firmly, make yourself look larger, and slowly back away—do not crouch or run. If you see a snake on the trail, stop and give it space—most bites happen when people try to move or handle snakes. Walk around from a safe distance.

Ticks are also a natural part of Orange County’s wildlands, especially in grassy or brushy areas. Stay on designated trails, wear long sleeves and pants, and do a tick check after your hike. A little awareness goes a long way!
: We’ve got hundreds of miles of established trails—staying on them ensures your safety and minimizes disruption of the incredible habitats you’re exploring.
: E-bikes are great for urban settings. And hugely destructive for natural spaces. To ensure our habitats’ survival, e-bikes are not permitted on the Reserve.
: We love dogs, but even leashed pets disrupt natural habitats. Help us keep the Reserve’s ecosystems in balance by either leaving your dog(s) at home or making sure you bring them to a dog-friendly area of the Reserve. Find out more about the parks that welcome pets here.
: Take a few deep breaths instead! This safeguards the health of other visitors, prevents waste and wildfires, and protects our plant and animal life from pollution.