Irvine Ranch Open Space Preserve

OC Parks’ Irvine Ranch Open Space began with the Irvine Company’s donation of about 20,000 acres, which the Orange County Board of Supervisors accepted in 2010 for preservation and guided recreation. More land was donated in late 2014, and the open space now covers nearly 25,000 acres of the county’s eastern foothills.

It sits within the larger Irvine Ranch Natural Landmarks. The Irvine Ranch was named a National Natural Landmark in 2006 for its geological and ecological significance, and in 2008 it became the first California Natural Landmark. In all, more than 50,000 acres of the historic Irvine Ranch are permanently protected.

This guide covers OC Parks’ Irvine Ranch Open Space, which is open only on Wilderness Access Days and during scheduled programs, plus the neighboring Natural Landmarks parks you can visit any day. Those daily parks are run by the City of Irvine, the City of Newport Beach, California State Parks, OC Parks and the Irvine Ranch Water District.

All Irvine Ranch Conservancy and OC Parks activities in these lands are free and listed at letsgooutside.org. Wilderness Access Days are monthly, self-guided Saturdays, and each area’s day is posted on that calendar. Black Star Canyon and Gypsum Canyon access days need no registration, and Saddleback Wilderness has monthly Exploration Days that also need no registration. Red Rock and Limestone Canyon require advance registration. Docent-led hikes, bike and equestrian rides, fitness hikes and stewardship programs all require registration. During open times, trails are used for hiking, mountain biking, and equestrian use.

How to Visit

Open Daily: Natural Landmarks Parks

These parks sit inside the Irvine Ranch Natural Landmarks but outside OC Parks’ access-day lands, so you can visit any day they’re open. Trails can close after rain, so check before you go.

Bommer Canyon

Run by the City of Irvine, Bommer Canyon has ancient groves of oak and sycamore and rugged rock outcrops. Its designated trails are open daily for hiking and mountain biking, and equestrians can use them May 1 through Nov. 30 only. The rest of the preserve opens only for guided programs and monthly Wilderness Access Days. The historic Cattle Camp has Open Access hours on the third Friday through Sunday of each month, 9 a.m. to 4 p.m.

Hours: Dawn to dusk
Dogs: Not allowed
Website: City of Irvine: Bommer Canyon Preserve

Buck Gully Reserve

Buck Gully is a natural canyon in Newport Beach, bordered by homes and businesses and managed by the City of Newport Beach. Its watershed covers about 1,200 acres, and docent-led activities run here too.

Hours: Dawn to dusk
Dogs: Not allowed
Website: City of Newport Beach: Buck Gully

Crystal Cove State Park

Crystal Cove is part of the Irvine Ranch Natural Landmarks and is run by California State Parks. Day use covers hiking trails, beaches and tidepools.

Hours: Day use 6 a.m. to sunset
Parking: $15 per vehicle per day, $20 on holidays and summer weekends; the Los Trancos lot is $5 an hour, up to $15
Website: California State Parks: Crystal Cove

Irvine Regional Park

Irvine Regional Park wasn’t part of the 2010 donation. James Irvine gave it to the county in 1897, making it Orange County’s oldest park and California’s first regional park. OC Parks runs it, and it’s home to the Orange County Zoo ($2). Independently run extras include pony rides (Tuesday through Sunday, cash only), the Irvine Park Railroad, bike and paddle-boat rentals, and horse rentals by appointment. The Irvine Ranch Outdoor Education Center is reached through the park.

Hours: 6 a.m. to 6 p.m. in fall and winter, 6 a.m. to 9 p.m. in spring and summer
Parking: $3 weekdays, $5 weekends, $7 on some holidays; the lot can close to cars when it fills on weekends
Dogs: Allowed on a 6-foot leash
Website: OC Parks: Irvine Regional Park

Laguna Coast Wilderness Park

Laguna Coast Wilderness Park covers about 7,000 acres with some 40 miles of multi-use trails, run by OC Parks from several staging areas. 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 the park. Nix Nature Center is open Monday through Friday 8 a.m. to 3:30 p.m. and weekends 9 a.m. to 2 p.m.

Hours: 7 a.m. to sunset (parking lot 8 a.m. to 5 p.m.); trails can close for three days or more after rain
Parking: $3 a day
Dogs: Not allowed
Website: OC Parks: 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 along Peters Canyon Creek. The 55-acre Upper Peters Canyon Reservoir draws resident and migrating waterfowl, though its water level depends on rainfall and drops during droughts.

Address: 8548 E. Canyon View Ave., Orange
Hours: 7 a.m. to sunset; trails can close up to three days after rain
Parking: $3 a day
Dogs: Allowed on a leash
Website: OC Parks: Peters Canyon Regional Park

Quail Hill

The 2-mile Quail Hill Loop Trail starts at the Quail Hill Trailhead at the end of Sand Canyon Road in Irvine. It’s the only wilderness trail in the Natural Landmarks that allows dogs, on a leash. Call 949-743-5943 for a free phone audio tour as you walk. Trails beyond the loop open only for docent-led programs.

Hours: Dawn to dusk
Dogs: Allowed on a leash
Website: Let’s Go Outside: Quail Hill

San Joaquin Marsh Wildlife Sanctuary

Owned by the Irvine Ranch Water District, this 300-plus-acre freshwater marsh doubles as a natural water-treatment system and a wildlife sanctuary. It has about 12 miles of walking trails, and more than 300 bird species have been spotted here, which makes it a favorite for birdwatching.

Address: 5 Riparian View, Irvine
Hours: Dawn to dusk daily; free
Dogs: No pets or bikes
Website: IRWD: San Joaquin Marsh

Whiting Ranch Wilderness Park

Whiting Ranch covers about 2,500 acres, with 23 trails (about 17 miles) through riparian and oak woodland. Take the Red Rock Canyon Trail to see its striking rock formations. The Red Rock Canyon and Billy Goat trails are for hikers only. Whiting’s Red Rock Canyon isn’t the same place as OC Parks’ Red Rock Wilderness.

Parking: $3 a day at the Borrego lot (26701 Portola Pkwy., Foothill Ranch) or the Glenn Ranch lot (27901 Glenn Ranch Rd.)
Hours: 7 a.m. to sunset, except after rain
Dogs: Not allowed
Website: OC Parks: Whiting Ranch Wilderness Park

Upper Newport Bay is also part of the California Natural Landmarks lands; see our Upper Newport Bay guide for trails and visiting tips.

Access Days and Guided Programs Only: OC Parks’ Irvine Ranch Open Space

Most of the areas below belong to OC Parks’ Irvine Ranch Open Space, where parking is free and dogs aren’t allowed except on Black Star Canyon Road. Orchard Hills and Shady Canyon are part of the City of Irvine’s Open Space Preserve and are also open only for guided programs. Find dates and registration for every area at letsgooutside.org.

Black Star Canyon

Black Star Canyon features red rock cliffs and views across Orange County to the Pacific and Irvine Lake. Its history includes a deadly 1831 clash between trappers led by William Wolfskill and Native Americans, and local lore says the canyon is haunted.

Black Star Canyon Road, a county road, is always open to the public and leads into the Cleveland National Forest. The OC Parks trails open on monthly Wilderness Access Days, which need no registration (the listing runs 8 a.m. to 2 p.m., with rangers clearing trails by 2 p.m.), and for scheduled programs such as docent-led hikes and bike rides in Baker Canyon.

Dogs: Allowed on Black Star Canyon Road only
Website: Let’s Go Outside: Black Star Canyon

Fremont Canyon

Fremont Canyon has massive granite cliffs, earning it the nickname “Yosemite of Orange County.” It’s also home to many rare and endangered plants and animals. Programs include distance hikes, mountain bike rides and equestrian rides, and registration is required for all of them.

Access: Scheduled programs only, with registration; free
Website: Let’s Go Outside: Fremont Canyon

Gypsum Canyon Wilderness

Gypsum Canyon Wilderness opened 500 acres of new park space in November 2023, with 6 miles of trails for hiking, biking and horseback riding and two lookout points. Its monthly Wilderness Access Days need no registration, and registered programs run here too.

Address: 390 S. Gypsum Canyon Rd., Anaheim
Parking: Free
Dogs: Not allowed
Website: Let’s Go Outside: Gypsum Canyon Wilderness

Limestone Canyon

Limestone Canyon is known for The Sinks, a striking geological formation often called a “miniature Grand Canyon,” along with oak woodlands and streamside habitat. Access is by scheduled programs with advance registration only, including Limestone Wilderness Access Days. OC Parks also holds occasional Agua Chinon and the Sinks Exploration Days from the Portola Staging Area, which require preregistration.

Parking: Augustine Staging Area (5524 Santiago Canyon Rd.) or Portola Staging Area, depending on the program
Website: Let’s Go Outside: Limestone Canyon

Loma Ridge and Hicks Haul Road

Loma Ridge, next to Limestone Canyon, has grassland and oak woodland trails with sweeping views, open through guided activities only. The Irvine Ranch Conservancy also runs recurring fitness hikes on paved Hicks Haul Road, about 3.5 miles to the top of Loma Ridge and back; check letsgooutside.org for the current schedule.

Website: Let’s Go Outside: Loma Ridge

Orchard Hills

Part of the City of Irvine’s Open Space Preserve, Orchard Hills sits next to a working avocado orchard, with views from Loma Ridge. Its multi-use trails include a strenuous 3-mile outer loop and an easy 1.2-mile inner loop. Access is by guided programs only.

Website: Let’s Go Outside: Orchard Hills

Red Rock Wilderness

Hike over 20- to 40-million-year-old red rocks in this 1,500-acre area, which has more than 8 miles of trails and an overlook with 360-degree views. It’s open through scheduled programs with advance registration only, including Wilderness Access Days and docent-led programs.

Parking: Free, at the Augustine Staging Area, 5524 Santiago Canyon Rd., Silverado
Dogs: Not allowed
Website: Let’s Go Outside: Red Rock Wilderness

Saddleback Wilderness

Saddleback Wilderness opened in March 2023 with 3.3 miles of biking, hiking and equestrian trails and 360-degree views. The land has an unusual past: in 1967 it became the first motocross park in the U.S. Monthly self-guided Exploration Days need no registration, and scheduled programs run here too.

Address: 3081 Santiago Canyon Rd., Orange
Parking: Free
Dogs: Not allowed
Website: Let’s Go Outside: Saddleback Wilderness

Shady Canyon

Shady Canyon is part of the City of Irvine’s Open Space Preserve. Unlike Bommer Canyon and Quail Hill, it has no daily self-guided trails, so you can visit only on docent-led activities listed at letsgooutside.org.

Website: City of Irvine: Open Space Preserve

Weir Canyon Nature Preserve

Weir Canyon’s deep canyons and steep hillsides hold what the Irvine Ranch Conservancy calls one of the largest and healthiest oak woodlands in Orange County. Access is by docent-led hikes and rides only, with preregistration; programs are free.

Website: Let’s Go Outside: Weir Canyon

Wildlife and Plants

These lands hold native grasslands, oak woodlands, coastal sage scrub and stream corridors, along with varied rock types and fossils of extinct species, including duck-billed dinosaurs. The City of Irvine highlights protected species such as the coastal California gnatcatcher, cactus wren and orange-throated whiptail. You might also spot golden eagles, red-tailed hawks, roadrunners, bobcats, mule deer, coyotes and dozens of butterfly species, and mountain lions and badgers live here too. Ticks and tarantulas are part of the mix.

Plant life ranges from rare Tecate cypress to white and black sage, toyon, lemonadeberry, California buckwheat and spring wildflowers like California poppies, arroyo lupine and owl’s clover. Watch for poison oak. Crews and volunteers also work to remove invasive weeds such as artichoke thistle, yellow starthistle, fennel, arundo, tamarisk and castor bean.

Know Before You Go

• Registration is required for docent-led programs and for some access days; check each area’s listing on letsgooutside.org.
• Dogs aren’t allowed in OC Parks’ Irvine Ranch Open Space, Bommer Canyon, Buck Gully, Laguna Coast or Whiting Ranch. Leashed dogs are OK on the Quail Hill Loop, at Peters Canyon and Irvine Regional Park, and on Black Star Canyon Road.
• E-bikes aren’t allowed on unpaved OC Parks trails or anywhere in the City of Irvine’s open space.
• Trails close after rain, for three days or more at some OC Parks parks. Check OC Parks Alerts and letsgooutside.org before you drive.
• Minors must wear helmets when biking.
• You can connect to the Cleveland National Forest along the northeastern border of the open space.
• Bring plenty of water. Some trails have no water access.
• Wear socks or pants that cover your legs, since ticks are present in the area.
• Bring sun protection, a map and a charged phone, and pack out everything you bring in.
• For more information on locations, programs, and activities, visit OC Parks: Irvine Ranch Open Space and Irvine Ranch Natural Landmarks.

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