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Enjoy peace and solitude in the San Gabriel Mountains, only 1.5 hours from Los Angeles.

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8,245' 2,513 m


5,835' 1,779 m


2,413' 736 m


2,413' 736 m



Avg Grade (7°)


Max Grade (17°)

Dogs Leashed

Features Birding · Fall Colors · Spring · Views · Wildflowers · Wildlife

California State Route 39 no longer connects with Highway 2. Winter conditions can cause road closures on 39, so be sure to check before traveling to the Crystal Lake Recreation Area.


The Mount Islip Loop takes you through the Crystal Lake Basin in the San Gabriel Mountains to the summit of Mount Islip (8,251ft.) and back. The trailhead is only 1.5 hours from downtown making for a convenient mountain hike if you are in or near the city. The visible fire scars from the historic 2002 Curve Fire, and the closed connection of California State Route 39 to Highway 2 has greatly lessened the popularity of the area giving today's visitors peace and solitude while on the trail.

The San Gabriel Mountains are some of the fastest eroding mountains in the world, and with the past fire damage extreme erosion, this is now even more of a problem. The actual trail surface is fairly stable for the most part; though please stay on the trail as the surrounding terrain is still in the process of re-vegetation, which will help prevent erosion over time.

Need to Know

Be sure to enjoy food, beverages, and ice cream at the Crystal Lake Snack Bar and Trading Post before or after your outing. You can rent the nearby cabins at the Trading Post, or stay at the nearby U.S. Forest Service Campgrounds if you would like to stay overnight. The Mount Islip Loop briefly connects to the Pacific Crest Trail along the Mount Islip Ridge; giving you options to connect with other peaks and trails in the San Gabriel Mountains. Adventure Pass required to park at trailhead.


The Mount Islip Loop is a combination of four trails: Windy Gap Trail #9W06 , Mt. Islip Trail #9W05, Islip Ridge Trail #9W08, and the Big Cienega Trail #9W07. The 7.4-mile loop starts and finishes in the Crystal Lake Recreation Area, in the Angeles National Forest at the Windy Gap Trailhead. There is a nice big paved parking lot with vault toilets making for a nice meet-up location for groups.

The Windy Gap Trail #9W06 first takes you up 1,740 feet over 2.5 miles to Windy Gap, a pass along the Islip Ridge. During the ascent through the Crystal Lake Basin, you'll see remnants of the 2002 Curve Fire that devastated the area. Some of the trail's terrain is loose though volunteers have done a good job containing major washouts and clearing the trail of loose rocks.

When you reach Windy Gap, you can access the Pacific Crest Trail that runs from Mexico to Canada. You'll continue northwest (left fork) on Mt. Islip Connector Trail until you reach the junction with the Mt. Islip Trail #9W05. From this junction, ascend west (left) on the Mount Islip Trail to the summit of Mount Islip.

You'll pass the junction with the Islip Ridge Trail #9W08 below the summit, which continues straight along the ridge. You'll come back to this junction and use it for your descent. After reaching the summit, you'll find ruins of an old stone cabin that was built to house the fire lookout that was once stationed on the summit. From Mount Islip summit there are panoramic views of San Gabriel Canyon to the south and the Mojave Desert to the north.

After enjoying the summit and catching your breath, first begin your short descent south where you'll join up with the Islip Ridge Trail #9W08. From here, hike west (right) down the Islip Ridge Trail #9W08. During your descent, you'll pass some rare limber pines along the ridge. Along the way, you'll have a clear view back east across the Crystal Lake Basin to Windy Gap along the Islip Ridge. This section of trail has very evident fire scars from the 2002 Curve Fire but the area is recovering well and the trail is in good shape.

After descending the Islip Ridge Trail #9W08, you'll come to a junction with the Big Cienega Trail #9W07 (left turn), which will lead you back to the Windy Gap Trail #9W06. This is a fun descent and a good trail to pick up some speed as the trail widens and the terrain is flatter. You'll pass through patches of Jeffrey and sugar pines along with white fir that survived the fire and cross a spring with wildflowers about midway. When you reach the junction with the Windy Gap Trail #9W06, turn right and continue on the homestretch downhill to the trailhead.

Use this last section of flatter terrain for your cool-down, before making it down to the car. After making it to the trailhead parking lot, reward yourself with some food, beverages, and ice cream at the Crystal Lake Basin Snack Bar and Trading Post.

Flora & Fauna

The Crystal Lake Basin provides beautiful 360-degree scenery of alpine flowers and various types of coniferous trees. Though here wildfire scars can be seen across the basin left over from the 2002 Curve Fire, a reminder that the San Gabriel Mountains landscape is ever-changing.

History & Background

Crystal Lake Recreation area was at one time accessible from Highway 2, Angeles Crest Highway. Though, in 1978, a landslide destroyed a section of California State Route 39 four miles from Crystal Lake. The California Department of Transportation has repaired this section but it remains closed to public use due to ongoing maintenance issues.


Shared By:

Taylor Reilly

Trail Ratings

  4.2 from 9 votes


  4.2 from 9 votes
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Big Cienega Trail looking east towards Hawkins Ridge
Oct 12, 2017 near Wrightwood, CA
Trailhead near parking lot.
May 3, 2021 near Wrightwood, CA
Mt. Islip Ridge looking south towards Azusa Canyon
Sep 28, 2018 near Wrightwood, CA
Caretakers Cabin?  Mt. Islip
Sep 28, 2018 near Wrightwood, CA
View San Gabriel Canyon and the distant Los Angeles Basin
Jul 21, 2015 near Wrightwood, CA
Mt. Islip Ridge looking West
Sep 28, 2018 near Wrightwood, CA



Current Trail Conditions

All Clear 23 days ago
Add Your Check-In


Sep 24, 2023
Charles Yoo
7.6mi — 3h 30m
Apr 23, 2023
May 29, 2022
Ted Kaufmann
May 31, 2020
Roman de Jesus
Apr 13, 2019
Jillian R
Bring your microspikes! There are still significant snow patches past Windy Gap.
Nov 18, 2018
M Weston
Oct 22, 2018
Brennan Boland
Sep 29, 2018
Brandon Hanna

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