Pets allowed
Allowed with Restrictions
Elevation Gain
9,608.00 ft (2,928.52 m)
Trail type
Loop
Distance
38.60 mi (62.12 km)
Please respect the outdoors by practicing Leave No Trace. Learn more about how to apply the principles of Leave No Trace on your next outdoor adventure here.

As the name entails, this is just a big, 38.6-mile loop in the San Gabriel Mountains in Angeles National Forest. It is a great opportunity to see some of the best parts of the range, especially the front country just above Altadena. There are a great many options to tackle this project, from section hiking, to a multi-day backpacking trip, to one big trail run. There are also a number of trailheads from which to begin: Red Box Picnic Area, Mt. Wilson Road, Millard Trail Camp, and Switzer Falls. One could find options to camp at a number of established backcountry trail camps along the way. Assuming a clockwise route from Red Box, camping opportunities are located at Valley Forge Trail Camp (2.3 miles, just off-route); Henninger Flats (11.6 miles, 1.2 miles off-route); Idlehour Trail Camp (13.1 miles, on-route); Mt. Lowe Trail Camp (17.25 miles, on-route); and Gould Mesa Trail Camp (27 miles, on-route). 

There are long sections of this route that are exposed and without water, which can make for a challenging trip in the height of the summer. Additionally, there is significant elevation change as the route navigates up, down, and across the San Gabriels. While much of the loop consists of maintained and well-established singletrack trails, there can exist sections that are less-maintained (notably on the Gabrielino Trail between Paul Little Picnic Area and the Switzer Junction). In these areas especially, one needs to be aware of rampant poison oak. During the winter and early spring, significant water crossings may be necessary (again, mostly on the Gabrielino Trail), while in summer and fall, creeks may run dry. Check trail conditions before embarking on this adventure, and be well-prepared for seasonal hazards.  Adventure Passes are required to park at Switzer Falls, Red Box Picnic Area, and Millard Falls.

Logistics + Planning

Preferable season(s)

Winter
Spring
Fall

Congestion

Moderate

Parking Pass

Adventure Pass required

Open Year-round

Yes

Days

2

Pros

Scenic Vistas. Flowing Creeks.

Cons

Exposed. Poison oak.

Trailhead Elevation

4,578.00 ft (1,395.37 m)

Highest point

5,660.00 ft (1,725.17 m)

Features

Backcountry camping
Historically significant
Waterfalls
Geologically significant
Big vistas
Wildflowers
Bird watching

Typically multi-day

Yes

Permit required

No

Location

Nearby Lodging + Camping

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