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Irvine Ranch Open Space Preserve

The Irvine Ranch Open Space Preserve was acquired in 2010 as a generous donation to Orange County for the purpose of guided recreational activities and preservation.

The 20,000 acre land donation, paired with additional land owned by historic Irvine Ranch, has been designated a Natural Landmark at the State and National levels for their geological and ecological significance, and is part of 50,000 acres of land that is permanently protected.

Irvine Ranch Open Space Preserve

The land and trails in the Irvine Ranch Open Space Preserve are accessible via regularly scheduled free programs open to the public. Many of the trails are closed to the public except for on scheduled Wilderness Access days in order to preserve and protect the lands. During accessible time periods, trails are open for a variety of activities including hiking, mountain biking, and equestrian use.

Within the protected land lies biological treasures such as native grasslands, live oak woodlands, and stream corridors that create natural habitats for rare and endangered plant and animal populations. There are also several unique geological features including a variety of rock types, varying terrain, and fossils of extinct species, including duckbilled dinosaurs.

What To Explore

Park Areas Open Daily to the Public

Bommer Canyon – trails include access to ancient groves of oak and sycamore and rough rock outcrops. Trails extending from Bommer Canyon trailhead and Bommer Vista Point are open daily, but some trail farther in such as East Fork and Ridge Route are only open on scheduled Wilderness Access Days.

Buck Gully Reserve – Buck Gully is a natural canyon running through Newport Beach bordered by homes and businesses.

Crystal Cove State ParkCrystal Cove is part of the Irvine Ranch Open Space lands and is operated by the State Park system. Entry to Crystal Cove is $15 per vehicle and includes access to hiking trails, beaches, and tidepools.

Irvine Regional ParkIrvine Regional Park is part of the Irvine Ranch Open Space land and is operated by the Orange County Parks system. Irvine Regional Park is open daily and is also the site of the Orange County Zoo. Visitors to the park will enjoy many amenities (most for an additional fee) including pony rides, Irvine Park Railroad, the nature center, a fishing lake, hiking trails, horse rentals, and more. The Irvine Ranch Outdoor Education Center is also located in Irvine Regional Park.

Laguna Coast Wilderness ParkLaguna Coast Wilderness Park is operated by the OC Parks system and includes multiple staging areas for access to many miles of multi-use trails. Nix Nature Center, Barbara’s Lake, Willow Staging Area, Little Sycamore Canyon Staging Area, James Dilley Greenbelt Preserve, Dilley Staging Area, and Big Bend Staging Area are all part of Laguna Coast Wilderness Park.

Peters Canyon Regional Park – Visitors will find a mix of roads and trails at Peters Canyon with groves of black willows, sycamores, and cottonwoods. Peters Canyon Creek runs through the park, but the lake is generally empty.

Quail Hill – The 2-mile Quail Hill Loop Trail at the Quail Hill Trailhead is located at the end of Sand Canyon Road in Irvine and is open daily to the public. Additional trails that extend beyond this are only open during scheduled docent-led programs.

Whiting Ranch Wilderness Park – Visitors to Whiting Ranch will enjoy trails that extend through riparian and oak woodland. Take the Red Rock Canyon Trail to see the spectacular geological formations.

Park Areas With Wilderness Access Days

Black Star Canyon – Blackstar Canyon features stunning red rock cliffs and views of the Orange County area including the Pacific Coast and Irvine Lake. The Blackstar Canyon area is rich in history and includes tales of fatal conflicts between trappers and Native Americans in the 1800s. Many believe that the canyon is haunted, and there are programs that take brave hikers out on night hikes to learn the tales of the deadly activities that took place here in the past. Other programs here include twilight hikes, equestrian rides, tai chi, and art programs.

Fremont Canyon – Fremont Canyon offers scenic views of massive granite cliffs and is often referred to as the “Yosemite of Orange County.” Fremont Canyon is also home to many rare and endangered plant and animal species. Fremont Canyon programs include distance hikes, mountain bike rides, and equestrian rides. Registration is required to participate in programs at Fremont Canyon.

Gypsum Canyon Wilderness – 500 acres of new park space opened in November 2023, with 6 miles of trails for hiking, biking, and equestrian riding. Only accessible on wilderness access days and registration is required.

Limestone Canyon – Explore Limestone Canyon to see a remarkable geological formation called The Sinks – an area that is often referred to as a miniature Grand Canyon. You’ll also find oak woodlands and streamside habitats. Programs at Limestone Canyon include hikes over 11 miles round-trip. A hike to the sinks and back is 6-8 miles.

Orchard Hills – Features multi-use trails with a strenuous 3-mile outer loop and an easy 1.2-mile inner loop.

Saddleback Wilderness – Opened in March 2023, Saddleback Wilderness offers 3.3 miles of new biking, hiking, and equestrian trails with 360-degree panoramic views. Accessible on select wilderness access days and select scheduled programs.

Black Star Canyon Stream
Black Star Canyon

Who Lives Here

Animals & Arthropods

Golden Eagles, mountain lions, badgers, bobcat, turkey vulture, greater roadrunner, gopher snake, western fence lizard, western toad, desert cottontail, California ground squirrel, coyote, mule deer, red harvester ant, darkling beetle, California quail, mourning dove, Anna’s hummingbird, acorn woodpecker, coastal cactus wren, western scrub-jay, California gnatcatcher, red-tailed hawk, white-tailed kite, common raven, Cooper’s hawk, barn owl, raccoon, Sara orangetip butterfly, bramble hairstreak butterfly, Western tiger swallowtail, cabbage white butterfly, common buckeye butterfly, common ringlet butterfly, funeral duskywing butterfly, orange sulfur butterfly, acorn blue butterfly, Monarch butterfly, tarantula, red bug, ticks, common green darner, milkweed beetle, European honeybees, tarantula hawk, jerusalem cricket (potato bug).

Plants & Invasive Weeds

Tecate Cypress trees, poison oak, sugar bush laurel sumac, toyon berry, lemonadeberry, white sage, California buckwheat, black sage, chia sage, coastal sagebrush, California poppy, arroyo lupine, common eucrypta, monkey flower, Owl’s clover, cliff aster, fiesta flower, goldfields, blue-eyed grass, fiddleneck, bush mallow, California encelia, deerweed, fuchsia flowered gooseberry, blue dicks, artichoke thistle, milk thistle, sahara mustard, black mustard, garland chrysanthemum, yellow starthistle, fennel, arundo, tamarisk, Spanish broom, castor bean.

Know Before You Go

Trail ratings vary from location to location. Be sure to check the trail maps to determine difficulty levels before you go on a hike or ride. Some trails are extremely difficult with dramatic changes in elevation, while others are easy with no elevation change. Plot your path before heading out.

  • Registration is required for scheduled programs and activities.
  • Dogs are not allowed in Irvine Ranch Open Space Preserve.
  • You can connect to the Cleveland National Forest along the northeastern border of the preserve.
  • Bring Plenty of water to hydrate during your activity. Some trails may not have access to water.
  • Always wear socks or pants that cover your legs – ticks are present in the area.
  • Bring along the standard hiking essentials – sunblock (always apply before you hit the trail), hat, glasses, snack, map, backpack, cell phone, and a first aid kit.
  • Remember to take only pictures and leave only memories, and to pack out what you packed in.
  • For more information on locations, programs, and activities, visit Irvine Ranch Open Space Preserve and Irvine Ranch Natural Landmarks.
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Heidi Deal
Heidi Deal is the author of the Newcomers Handbook to Living In Los Angeles & Orange County, and a children’s book author specializing in history and human rights. When she's not writing you can find her solo hiking and going on new adventures with her kids and pup.