39 heading out of Azusa, California at the headwaters of the north fork of the San Gabriel River at an elevation approximately 5,539 feet (1,688 m) above sea level.

Because the campgrounds could be accessed from Angeles Crest Highway prior to the 1978 landslide,[6] which demolished a half-mile section of California State Route 39 four miles (6 km) from Crystal Lake, Hollywood performers and other Los Angeles celebrities and politicians used to frequent the campgrounds because of the easy access across the San Gabriel Mountains.

In 1969, a severe rainy season flooded the restrooms on the shoreline, and the water became contaminated to the point that the swimming facilities were closed.

Subsequent rainy seasons flooded the small cabin that served as a summer residence for concessionaires who operated a snack stand from the lower level and patio, and by 1990 the facility was demolished.

The main facilities consist of a general store which grew from a small tackle house in the 1950s, to a fast food snack stand by the 1970s, rental cabins from the olden days, a residence for the concessionaires, service sheds and garages, an ice cream stand which opened in the summer, and a ranger station, which by 1990 had become a visitors center managed by forestry volunteers.

In later years as the building deteriorated, the floor was left in open air, and a small shed was put up to house a juke box.

Just past the old dance floor is the amphitheater where campfire programs were used to gather the campers in the evening for group sing-alongs and maybe a nature film.

Due to budget constraints, the remoteness of the area and other maintenance and logistics problems, the campground has faced closures of several camp sites reducing the number by nearly 100.

Management contractors were brought in to help run the facility, but in 2002 the Curve Fire burned through the canyons and the basin which forms the Recreation Area, prompting the campgrounds to be closed altogether for health and safety reasons.

[8] One of the most interesting features of the Crystal Lake Recreation Areas is the amphitheater which was built by the Civilian Conservation Corps and other agencies and was fully restored after the damage to the facility caused by the Curve Fire of 2002 by contractors.

This open facility is often used by U. S. Forest Service volunteers and employees to give lectures to individuals, Boy Scouts, hikers, campers, and picnickers during the day and often at night.

A drinking fountain located on the walkway to the facility provides water taken from an underground cistern fed by Soldier Creek.

The Visitor Center is located across the parking lot from the kitchen and general store (which is run by a private individual and not by the USFS.)

There is a cafe that features a potbelly stove and an open patio with a number of tables next to an array of gas and charcoal grills for outdoor cooking.

As a recreation area the campground had many nature trails for visitors which provided scenic and educational walks through various parts of the canyon: Pinion Ridge, Soldier Creek, Knob Hill, Golden Cup, Tototgna to name a few.

The hiking and nature trails located within the Crystal Lake Recreation Area as well as within the surrounding San Gabriel River Ranger District of the United States Forest Service are restored, repaired, and maintained by the San Gabriel Mountains Trailbuilders which brings in and coordinates other volunteers from Southern California and surrounding States.

For some of the nature trails—such as Golden Cup and Lake Trail—maintenance and repair has consisted of volunteers hauling in many thousands of pounds of rock, gravel, and sand using buckets to fill in sections of the trails which have been damaged by rainfall.

The San Gabriel Mountains Trailbuilders provide the tools, equipment and planning required for maintenance of the trails, soliciting and coordinating additional volunteers from organizations such as Buddhist Youth Groups, Boy Scouts of America, church groups, hiking, biking, and climbing clubs, High School students, and court-ordered Community Service individuals.

Trail maintenance within the Crystal Lake Recreation Area never ends and because of the dedicated efforts of volunteers, the campgrounds boast of many enjoyable and reasonably safe hikes.

Other Recreation Area problems such as spray paint vandalism, leaking water outlets, overflowing camp sites or BBQ boxes may also be reported to the Trailbuilders as well as to the U. S. Forest Service Glendora, California offices at (626) 335-1251, Monday through Friday from 8:00am to 4:30pm.

Because Deer Flats is intended for large groups, downed trees are situated around the larger fire rings in most of the camp sites for seating.

There are several toilet buildings located toward the Southern end of Deer Flats Group Campgrounds which have been installed after the Curve Fire swept through the area.