- Location: Corona, near the Orange/Riverside County boundary. From the 91 Freeway, take the Green River exit and head west for half a mile to a parking lot on the right side of the road, a quarter mile before the entrance to the golf club.
- Agency: Coal Canyon Ecological Reserve/Cleveland National Forest (Trabuco Ranger District)/Chino Hills State Park
- Distance: 12.7 miles
- Elevation gain: 2,600 feet
- Difficulty Rating: R (Distance, steepness, elevation gain, terrain)
- Suggested time: 6.5 hours
- Best season: November – March
- Dogs: Not allowed
- Cell phone reception: Good for most of the route; weak to none in a few spots
- Water: None
- Restrooms: None
- Camping/backpacking: None
- Recommended gear: sunblock; sun hat; hiking poles
- More information: Trip description here; MeetUp description here; AllTrails report (out and back; fire break route shown on map) here
- Rating: 7
Updated December 2018
If you are an outdoor lifestyle influencer and you are looking for a beautiful spot for some inspirational photos to share on social media, you won’t find it here. That being said, while this hike up Sierra Peak’s western slope won’t win any points for style, it offers one of the best workouts in northern Orange County and the southwestern corner of the Inland Empire. This route is shorter and has less elevation gain than the approach from the east – and is arguably less scenic, as it starts and ends with a mile-plus stretch next to the freeway on a bike path and indeed never really escapes the sights or sounds of traffic – but the climb up the fire break makes this a great training hike. As the northernmost summit of the Santa Ana Mountains (elevation 3,045), Sierra Peak offers views of all of So Cal’s major summits. This loop route, which ascends the fire break and descends via the Coal Canyon Truck Trail, visits two sites of note besides the summit: the Mini Moab rock formations and a grove of rare Tecate cypress trees which are recovering from the 2017 Canyon II fire. This is the northernmost point in the world where the trees grow.
From the parking area, follow the bike path for a little over a mile. In the late fall and winter, the changing colors of the leaves on the trees in the Santa Ana river bed make for a nice contrast to the drudgery of walking alongside the freeway. On the opposite side of the roadbed, you may notice the route of your ascent, the Pipeline Trail, cutting across the north slope of Sierra Peak. Cross under the freeway at the site of a former off-ramp that was closed in 2003 and has since become absorbed into Chino Hills State Park as a wildlife corridor. Soon the trail splits. Normally I prefer to hike loops in a direction that allows me to descend on the steeper leg, but this is an exception: while climbing up the fire break was not fun, I could imagine that going down it would be less fun, so I am going to recommend hiking clockwise.
Bear left (the Coal Canyon Truck Trail, on the right, is your return route). The “Big Mo” trail soon splits off, heading deeper into Coal Canyon toward a small seasonal waterfall. The Pipeline Trail makes a hairpin left turn and begins a steady ascent, picking up almost 800 feet in the next 1.4 miles. Though the freeway noise is hard to ignore, you get a good aerial view of it as you climb. At 2.7 miles from the start, the Pipeline Trail reaches a bench below a power line tower and starts to descend. Turn right and follow an unsigned but clear fire road steadily uphill for 0.7 miles (400 vertical feet) to the start of the fire break.
Now comes the business portion of the hike. The fire break ascends about 400 feet in the next quarter mile before reaching a gently rolling ridge that gives you a brief respite. You reach a T-junction. Turn right and begin the next grueling ascent which goes up another 400 feet or so before mercifully leveling out. At the top of the steep climb you’ll get your first good look at Sierra Peak, less than a mile away and only a few hundred feet above. Once the trail joins Leonard Road (Main Divide Road on some maps), turn left and climb a relatively easy 0.4 mile to Sierra Peak.
The antennas are hard to ignore, but the views of north O.C. and the Inland Empire are impressive nonetheless, especially on clear days. There is nothing taller between this point and the San Gabriels, so the views of Baldy and Cucamonga Peak are excellent and particularly attractive if there has been recent snow.
After resting and taking in the panorama, begin the long descent. Follow Leonard Road past the top of the fire break. As the trail descends along a ridge, you are treated to good views on both sides: the interior of the northern Santa Anas on the left and Santa Ana Canyon on the right. In 2.5 miles, you reach the top of the Mini Moab formations. (This spot is also the destination of a hike offered by Irvine Ranch Conservancy a few times per year). The spot offers dramatic views of the formations and Fremont Canyon far below.
From here it is a pleasant 3.5 mile descent back to the floor of Coal Canyon, passing by some of the Tecate cypress trees and a few oaks that survived the fire. At the bottom of the Coal Canyon Truck Trail, retrace your steps back under the freeway and along the bike path toward your starting point.
Text and photography copyright 2018 by David W. Lockeretz, all rights reserved. Information and opinions provided are kept current to the best of the author’s ability. All readers hike at their own risk, and should be aware of the possible dangers of hiking, walking and other outdoor activities. By reading this, you agree not to hold the author or publisher of the content on this web site responsible for any injuries or inconveniences that may result from hiking on this trail. Check the informational links provided for up to date trail condition information.