The Mount Islip Loop Trail makes for a perfect day hike in solitude close to Los Angeles. The trail starts and finishes in the Crystal Lake Recreation Area of the Angeles National Forest. The loop trail is a combination of three trails, the Windy Gap Trail, the Islip Ridge Trail, and the Big Cienega Trail. It starts and ends at the Windy Gap Trailhead. The Windy Gap Trail takes you up 1,740 feet over 2.5 miles to Windy Gap, a pass along the San Gabriel crest. During the ascent through the Crystal Lake Basin you will see remnants of the 2002 Curve Fire that devastated the area. The Forest Service has since built nice new facilities, campgrounds, and restrooms. Though volunteers keep the trails maintained and well groomed, this part of the Angeles National Forest still remains heavily scarred.
At the gap you'll find a junction with the Pacific Crest Trail that runs from Mexico to Canada. From here you ascend the Islip Ridge Trail west to the summit of Mount Islip. On the summit there are ruins of an old stone cabin that was built to house the fire lookout that was stationed on the summit in the past. From the summit there are panoramic views of Azusa Canyon to the south and the distant Mojave Desert to the north. After descending down the Islip Ridge Trail you will join up with the Big Cienega Trail, which will lead you back to the Windy Gap Trail for your exit. Here you will again notice the scars left from the 2002 Curve Fire, a reminder that this landscape is ever-changing.