Mount Gleason is a large, hog-backed ridge forming the eastern high point of the Santa Clara Divide in the western San Gabriel Mountains, positioned opposite Pacifico Mountain near Mill Creek Summit on Angeles Forest Highway.
To the north of the Santa Clara Divide is the Santa Clara River drainage, and on the south is the Los Angeles River drainage. The 6500' summit elevation is somewhat moderate for the San Gabriel range, but the low elevations of surrounding canyons provide for a tremendous amount of releif. On the north, Soledad Canyon bottoms out at roughly 2800' elevation, giving the northern aspect of Mount Gleason a vertical rise of 3700'. On the south, Tajunga Canyon Reservoir is at 2200' elevation, providing 4300' of rise.
Though all sides of Mount Gleason are tremendously steep, the northern aspect has well-graded fire roads that see much traffic throughout the year. The riding is relatively gentle, with dense forests of ponderosa, jeffrey, and western white pine, Califorina live oak, alder, big leaf maple, and sycamore. Views of the western Mojave Desert and the Sierra Pelona and Canyon Country are quite impressive, especially on clear spring days when the red and brown desert hills are painted with the blue and orange of lupine and poppies and the green of fresh spring grasses.
The southern aspect of Mount Gleason is incredibly rugged. Sharp ridges of fractured granite radiate out to the large outlying mountains of Condor Peak, Fox Peak, and Iron Mountain. This latter peak sits atop the long Mendenhall Ridge, which hosts one of the longer 'backcountry' fire road routes in this part of the San Gabriels. The Mendenhall Ridge Road is also the access route for several tough singletrack routes - Pacoima Canyon Trail, Condor Peak Trail, Trail Canyon Trail, and Yerba Santa Trail. The terrain in this region is very rough, with the trails and roads traversing crumbling cliffs, and passing through mostly high-desert terrain with cactus, yucca, chapparal, buchthorn, and some sumac and live oak. The canyon bottoms provide what little shade can be found, with alder and sycamore.
Mount Gleason is named for George Gleason, first postmaster of the nearby town of Ravenna. In 1869, Gleason climbed the mountain looking for harvestable timber, but instead found gold. The Mount Gleason Mining District was active in this period, with the ore being transported down the mountain to a large stamp mill in Soledad Canyon.
In more recent times, the summit of Mount Gleason hosted a Nike missile base. Though no missiles currently are based here, many of the building foundations and silo caps can be found on the summit. Currently there are only a few water tanks and an old crumbling stone cabin on the summit.
Riding on Mount Gleason is mostly done on fire roads and the paved Mount Gleason Road. Though the singletrack trails on Mendenhall Ridge can be accessed from Mount Gleason, their distance from the summit and their extremely rugged character make for a tough day out. The main attraction for bicyclists in this area is the opportunity to do very long rides in a relatively remote setting. The long distances on well-graded roads make this area ideal for backcountry touring.
There are several access points for rides on Mount Gleason. The easiest riding, on the east and north, can be accessed either from Mill Creek Summit or from Aliso Canyon Road in Acton. From the west, where the most rugged riding is, access is either via the two ridges bracketing Pacoima Canyon (Mendenhall Ridge and the Santa Clara Divide), or from Tajunga Canyon on the south or Soledad Canyon on the north. These two major canyons also provide mid-point access to Mendenhall Ridge and the Santa Clara Divide.
Mill Creek Summit
From the I-5 / CA-14 junction north of Los Angeles, drive northeast on CA-14 to the CA-138 / Angeles Forest Highway exit. Continue south on Angeles Forest Highway for 9 miles to 5000' Mill Creek Summit. The paved Mount Gleason Road starts on the northwest side of the pass.
From the San Gabriel Valley and areas south and east of Los Angeles, drive to the I-210 / CA-2 junction in La Canada. Exit at CA-2 North, which is Angeles Crest Highway. Drive north on CA-2 to Clear Creek Junction and turn left onto Angeles Forest Highway. Continue north past Lower and Upper Big Tajunga Canyon Roads and on to Mill Creek Summit
To reach the western end of Mendenhall Ridge, exit I-210 at Little Tajunga Canyon in Pacoima. Drive north on Little Tajunga Canyon to Dillon Divide, where there is a small parking area. The Mendenhall Ridge Road leaves Dillon Divide to the north, and the Kagel Mountain Road leaves to the south.
Santa Clara Divide
The Santa Clara Divide can be most easily accessed at Bear Divide Picnic Area, on Sand Canyon Road. From the I-5 / CA-14 junction, drive northeast on CA-14 to the Sand Canyon Road exit. Go south on Sand Canyon past Placerita Canyon and Live Oak Picnic Area and continue up to Bear Divide, where there is a small picnic area with good parking and water. The Santa Clara Divide Road goes east from Sand Canyon Road a short ways northeast of the picnic area.
Red TapePermits are not required to ride or hike in the area, but some developed campgrounds and picnic sites require a Forest Adventure Pass for parking. A fire permit is required for camp fires and stoves while camping. Fire permits are free, and may be obtained at Chilao Visitors Center on Angeles Crest Highway.
There are 4 developed campgrounds nearby: Monte Christo, Messenger Flat, Big Buck, and Pacifico.
Monte Christo is located on Angeles Forest Highway, approximately 5 miles south of Mill Creek Summit. Fee required, pit toilets and water are available.
Messenger Flat is located on the Santa Clara Divide Road approximately 2 miles west of the summit of Mount Gleason. This campground has recently been renovated. Fee required, pit toilets available, but no water.
Big Buck is located on Big Buck Road (FS-4N24) approximately 1.5 miles north of Mount Gleason Road. This is a semi-developed site with tables but no toilets or water. No fee required.
Pacifico is a developed campground located on the summit of Pacifico Mountain approximately 6 miles east of Mill Creek Summit. Fee required, pit toilets available but no water.
Lightning Point group camp is located near where the Mendenhall Ridge Road leaves the Mont Gleason Road, approximately 0.25 mile west of the summit of Mount Gleason. This is a large group camp, and reservations and fee are required. Flush toilets, water, and equestrian facilities are available.
Chilao Flat is a bit more distant, but has more facilities, including a visitors center and Newcomb Ranch bar and cafe. Chilao also has a good selection of ridable trails.