Ask a longtime Brentwood hiker which canyon they'd pick for an 11 a.m. walk in late August, and for years the honest answer was whichever one had parking. Mandeville Canyon and Sullivan Canyon sit less than a mile apart off the residential streets north of Sunset, both climb old fire roads into the same wilderness park, both allow dogs, and both eventually reach the same stretch of unpaved Mulholland Drive at the top. People who live here talked about them as one hike with two front doors.
That stopped being true in January 2025. The Palisades Fire moved through the Santa Monica Mountains and reached into Mandeville Canyon, and what came out the other side is a trail that shares an address with its old self but not much else. Sullivan Canyon, a half mile west, never lost the canopy that used to make the two routes feel the same. The gap between them is now the whole reason to pick carefully.
The Two Trailheads That Used to Get Confused for Each Other
Mandeville's trailhead sits off Westridge Road near Garden Lane Road, about 4.8 miles north of Sunset Boulevard along Mandeville Canyon Road. Sullivan's is a short drive further west, at the end of Queensferry Road, reached by turning off Westridge and cutting through Bayliss Road. Both were built as service roads, both climb toward the same ridge system inside Westridge-Canyonback Wilderness Park, and both eventually intersect the dirt section of Mulholland Drive that locals just call "dirt Mulholland." For most of the last decade, choosing between them came down to which street had an open curb.
What the Fire Actually Left on the Ground
The Mountains Recreation and Conservation Authority closed the burned stretch of Mandeville for weeks after containment while rangers checked for weakened trees, loose rock, and damaged power infrastructure. The trails reopened roughly six months later, and a year and a half out from the fire, the recovery is visible but not the kind that brings shade back quickly. California buckwheat has moved into the burned slopes as an early erosion-control plant, laurel sumac is filling in behind it, and coast morning glory, also called island false bindweed, is climbing the blackened tree branches that are still standing. It is a genuinely good sign for the hillside. It is not a canopy.
Mandeville was already a trail with little natural shade even before 2025, a route where summer temperatures can hit triple digits with no reliable water source along the way. Losing what tree cover it had only sharpens that. A walk that used to be tolerable at 10 a.m. now runs hot noticeably earlier in the day.
Sullivan Canyon Kept What Mandeville Lost
None of the current trail descriptions for Sullivan Canyon mention fire impact, and the reason shows up the moment you're under the tree line. The canyon is still lined with sycamore and oak, with a seasonal creek running down the center that the local gas company has protected with concrete crossing mats, marked every few hundred feet by yellow pipeline posts. Depending on where you turn around, the round trip runs somewhere between 8.5 and just under 10 miles, long enough that the shade matters for the whole outing rather than just the first mile.
The canyon has an older story than most hikers realize. In 1946, architect Cliff May developed Sullivan Canyon Ranches on this land, laying out communal stables and bridle trails for a rustic equestrian community. That history is still visible about half a mile in, where a riding ring sits on land still zoned for horses. It's part of why the canyon reads as a working landscape rather than a manicured park trail, and part of why the tree cover that survived the fire feels older and denser than anything replanted after it.
Where the Two Canyons Meet Again
Both routes top out near the same stretch of dirt Mulholland, which runs along the ridge to San Vicente Mountain Park at 17500 Mulholland Drive in Encino. The 10.2-acre park is the former LA-96C site, one of sixteen Nike-Ajax anti-aircraft missile installations that ringed Los Angeles from 1956 to 1968, built to track incoming aircraft with ground-based radar and guide missiles that would have launched from Sepulveda Basin. The Army decommissioned the site by 1974 as the technology aged out, and the Mountains Recreation and Conservation Authority now maintains it with self-guided interpretive panels explaining the layout.
Stairs still lead up the old radar tower, and the view from the top runs across the Encino Reservoir, the San Fernando Valley, and back toward the Los Angeles Basin, which makes it one of the better places on this side of the mountains to watch the sun go down. It's also the rare stop on either canyon route with a working restroom and a water fountain. One regular visitor's account notes the gate to the observation deck opens before 7 a.m., which matters if a sunrise trip is the plan rather than sunset.
The same fire that stripped Mandeville's shade never touched the sycamores half a mile over in Sullivan Canyon. That's the entire reason two trails treated as interchangeable for years now call for different times of day.
The Leash Rule People Learn the Hard Way
Dogs are permitted off leash within Westridge-Canyonback Wilderness Park itself, under an owner's direct control, which is why the ridge above Mandeville has long been popular with people who let their dogs run. That permission ends the moment the trail meets Mulholland Drive, where leash rules apply again, a distinction that catches people who assume the whole ridge system follows one policy. Mountain bikers use Sullivan's single-track heavily where it crosses the wider central fire road, so it's worth watching for them on blind curves near the creek crossings. Regular hikers on the Westridge ridge trail also note young rattlesnakes becoming active in late summer, which is reason enough to keep dogs closer even in the stretches where off-leash is technically allowed.
Picking a Route by the Clock, Not the Map
Before 9 a.m., all three options behave about the same, whether it's Mandeville, Sullivan, or the Westridge fire road up to the Nike site. After 10 or 11 a.m. in August, the exposed sections of Mandeville and the open ridge stretch of Westridge run hot fast, with none of the shade that used to make a mid-morning walk comfortable. Sullivan stays walkable well into early afternoon because the canopy that survived the fire is doing exactly what canopy is supposed to do. If the destination is the view from the old radar tower, the better plan is going up Westridge in the cooler morning hours and treating the park itself, with its restrooms and water, as the turnaround rather than pushing further onto the exposed dirt Mulholland at midday.
Before you go:
- Mandeville Canyon trailhead area is near Westridge Road, about 4.8 miles north of Sunset Boulevard, with limited free street parking.
- Sullivan Canyon's trailhead is at 2120 Queensferry Road, with no dedicated lot and tight street parking on weekends.
- San Vicente Mountain Park sits at 17500 Mulholland Drive in Encino, with parking along Mulholland near the dead end and restrooms and drinking water on site.
- Off-leash access applies inside Westridge-Canyonback Wilderness Park under direct owner control, but not once you're on Mulholland Drive itself.
For anyone who's lived here long enough to alternate between these two canyons without a second thought, this is less a discovery than an update to a mental map that's been slightly wrong for the better part of two years. The trails didn't disappear. They just stopped being the same hike.
If Brentwood's day-to-day is starting to shape a longer conversation about where you live next, Jonas Heller is available to talk through it. Request a private consultation whenever the timing feels right.
