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blue El Prieto to Brown Mountain Loop

  3.8 ( 10 ) Favorite


8.2 mile 13.2 kilometer loop
89% Runnable


Ascent: 1,254' 382 m
Descent: -1,254' -382 m
High: 2,385' 727 m
Low: 1,152' 351 m


Avg Grade: 6% (3°)
Max Grade: 17% (10°)


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Trail shared by Justin Jasper

A challenging wooded climb, great views, and a fast descent.

Justin Jasper

Features Fall Colors · River/Creek · Views · Wildflowers · Wildlife


The best moderate loop in the Pasadena/Altadena front range of the San Gabriels. Although the El Prieto climb is a bit challenging, it's wooded, crosses multiple streams, and is pretty. The descent on Brown Mountain Road and Fern Truck Trail isn't too steep, has nice views, and can be done pretty fast.

Need to Know

Rocky, rooty, and a challenging uphill.

Runner Notes

This loop has a challenging ascent. Watch out for mountain bikers descending the El Prieto Trail. It is generally easy to let them pass, and they are always friendly, because it's a great trail.


From the parking lot near the JPL entrance, follow the paved trail that turns to a dirt road for about 1.25 miles. Take the right fork towards El Prieto/Brown Mountain for about 0.25 miles, then stay right onto El Prieto.

Follow this steep trail for about 2 miles until you reach Brown Mountain Fire Road. Turn left here and climb up to the saddle between Brown Mountain Fire Road and Fern Truck Trail. Descend down Fern Truck Trail (also called Brown Mountain; the left-most trail when you reach the saddle) back to the junction where you took El Prieto, and head back the way to came to the parking lot.

You can also do the loop in reverse, but running down El Prieto is a little less desirable. You can also add an out-and-back from the Brown Mountain Saddle towards Ken Burton Trail if you are looking for a longer run. El Prieto has a few off-shoots, but they'll all reach Brown Mountain eventually.

Flora & Fauna

Might see some coyotes, deer, and rabbits.

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Jan 3, 2018
Kyle Feig
Beautiful hike. Was scared to death a biker was going to hit me but going up the trial to the right and coming down on the left seemed to prevent that 6.8mi
Jun 15, 2017
Andrew Velasquez
Apr 2, 2017
Jose Hernandez
Pasadena Trail Race Series 10Mi 10mi — 1h 41m
May 14, 2016
Andy Kiehl
poison oak over trail on prieta — 1h 11m

Trail Ratings

  3.8 from 10 votes


in Pasadena


  3.8 from 10 votes
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