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A 9.2-mile dirt road leading past Henninger Flats up to Mt. Wilson.

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5,647' 1,721 m


1,241' 378 m


4,441' 1,354 m


130' 40 m



Avg Grade (5°)


Max Grade (16°)

Dogs Leashed

Features Commonly Backpacked · Views · Wildflowers

Motorized vehicles, including electric bicycles, not permitted.

Need to Know

Watch for parking restrictions in neighborhood near Pinecrest Drive. Please be considerate of local residents by keeping noise levels down and not blocking driveways. For camping and other information at Henninger Flats, call 626-794-0675.


Though not particularly steep, this dirt road is quite long, 9.2 miles one way. The road starts at the intersection with Pinecrest Drive and heads north out of the development on a mostly shadeless route dropping down and crossing a bridge over Eaton Canyon then climbing up the south facing side of the mountain. The trail intersects Eaton Canyon Path early on at 0.2 miles and the old "equestrian trail" at 0.8 miles. Henninger Flats is about 2.8 miles along the trail and is an excellent rest point. Although there is no water or flush toilets at Henninger Flats, the shade and a visitor center might make you reconsider continuing on. There is also a campground for overnight use.

But continue on you must if you want to reach the summit of Mt. Wilson, a daunting 6.4 miles away. The road continues north from the upper campground area offering views of the flats below then enters a nicely shaded area of oak and bigcone spruce. About 1 mile above the flats there is a junction with the Idlehour Trail 12W16 at a switchback in the road. The road continues climbing and reaches a saddle. There is a spur trail heading south up to a high point with fine views of the Los Angeles Basin.

The road continues north with good views of Eaton Canyon then turns east through another welcomed shady area passing over a saddle and turning north with views into Little Santa Anita Canyon. At around 8 miles there is a junction at Manzanita Ridge with the Mt. Wilson Trail on the right. The road continues north along the steep eastern side of Mt. Harvard and reaches another saddle with the Mt. Wilson Summit Spur Trail on the right. This trail saves about half a mile and leads directly to the large parking lot near the top. The road continues on the west side of the ridge and makes one long switchback ending at a junction with the Mt. Wilson Circle Road. To reach the parking lot and the pavilion, you need to go about 100' north and turn right through the gate if it is open.

There are nice views at the summit of Mt. Wilson and the Cosmic Cafe offers food and beverages (hours vary by season), but running to the top makes for a very long day.

Thanks to John McKinney, The Trailmaster, for sharing this trail description. To learn more about trails in California, check out his guides at The Trailmaster Store.

Flora & Fauna

There are numerous tree varieties in Henninger Flats such as knob cone, Coulter, sugar, gray and Jeffery pine. Also Japanese black pine and Himalayan white pine. Oak and bigcone spruce provide areas of shade along the road above the flats. Chaparral of scrub oak, ceanothus, laurel sumac and manzanita are widely seen along the way. Poison oak is common in the shady areas. Watch for rattlesnakes.


Shared By:

John McKinney

Trail Ratings

  3.6 from 8 votes


in Altadena


  3.6 from 8 votes
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25 Views Last Month
2,129 Since Aug 8, 2017
Intermediate Intermediate



Everything is clear at 5000ft above.  You can even see the tall buildings in Downtown Los Angeles!
Sep 22, 2015 near Sierra…, CA
View of Pasadena and beyond from Mt. Wilson
Sep 22, 2015 near Sierra…, CA
No snow on the sunny side of the mountain.
Mar 13, 2019 near Sierra…, CA
Views of Mt. San Antonio and Monrovia Peak from the toll road near the summit
Feb 8, 2019 near Sierra…, CA
Mt. Wilson Tollroad bridge.
Sep 29, 2016 near Altadena, CA
Telegraph Peak from Mt. Wilson Toll Road
Feb 21, 2018 near Sierra…, CA


Current Trail Conditions

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Apr 16, 2022
Private User
Oct 17, 2021
Christine Horton
Dec 28, 2018
The views save this from being a boring fire road slog. Remember to bring layers, the elevation delta makes a big difference. Time very approximate. 19mi — 6h 30m

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