One of the few peaks to break the 10,000 feet threshold in Southern California, Grinnell Mountain is the 12th tallest peak in the San Bernardino range, but 3rd in prominence with 479 feet.

Grinnell Mountain is in the San Gorgonio Wilderness Area.

The most easiest route to the summit starts at the Fish Creek Trailhead in the San Gorgonio Wilderness. Another popular but longer and slightly harder route to the summit of Grinnell Mountain is from the South Fork Trailhead in the San Gorgonio Wilderness. See the route section for direction to the trailheads and from the trailhead to the summit.

External Links

Sierra Club's Page

peakbagger.com's page

San Bernardino National Forest

San Gorgonio Wilderness Association

San Gorgonio Wilderness

The 58,700 acre San Gorgonio Wilderness is located in the southeast corner of the San Bernardino Mountains and includes the high peaks of the San Bernardino Mountains, which are mostly within the San Bernardino National Forest.

The San Gorgonio Wilderness is located approximately 75 miles east of Los Angeles, California. Elevation in the wilderness ranges from 4,500 feet to 11,499 feet on top of Mount San Gorgonio. In addition to Mount San Gorgonio there are eleven other peaks over 10,000 feet elevation. The San Gorgonio Wilderness contains the highest peaks in California between Mexico and the Sierra Nevada.

Vegetation within the area varies from desert to alpine flora and fauna. The area is characterized by well timbered northern slopes, small meadows, two small lakes, and rugged terrain. Water is scarce.

Seasons in the San Gorgonio Wilderness:
Summer: The San Gorgonio Wilderness during an average year may be snow-free from June through December. Average summer temperatures are 75� F to 80� F degree highs, with nighttime lows of upper 40's and lower 50's (Fahrenheit).

Winter: The San Gorgonio Wilderness generally receives it's first snows in late December - during drier years not until mid to late January. Snowpack can and may exceed ten feet in some areas during the winter and spring. Daytime winter highs are approximately 30's to 40's, with nighttime lows around 0-20 degrees Fahrenheit.

Red Tape

Quotas are in effect for all travel zones and permits are required for both day hikes and overnight trips. Camping is only allowed in designated sites.

Application for a Wilderness Permit:

Wilderness Permit Application>Wilderness Permit Application

You will also need an Adventure Pass to park at the trailheads for the hike to Grinnell Mountain.

For more information contact the Mill Creek Ranger Station (909-382-2882)

Route Information

The South Fork Trailhead is located on Jenks Lake Road, 2.5 miles from Highway 38. The elevation of the trailhead is 6,850 feet. Directions from the South Fork Trailhead to the summit to Grinnell Mountain are as follows:

From the parking area, hike the South Fork Trail past the old Poopout Hill trailhead to South Fork Meadows where the Dry Lake Trail forks left. Turn left (SE) and follow this trail 1 1/2 miles to Dry Lake where there is another trail fork. Turn left and go 1/2 mile to Lodgepole Spring. From Lodgepole Spring continue 3/4 mile east cross-country (use trail) up to Fish Creek Saddle at 9805 feet elevation. From Fish Creek Saddle, hike north on a use trail up the ridge to the summit. The hike is about 15 miles with 3,500 feet of elevation gain.

To reach the Fish Creek Trailhead, turn right (S) off Highway 38 about 6 miles past the Barton Flats Visitor Center on Forest Service Road 1N02. Follow 1N02 until it forks right to 1N05. Follow 1N05 (rough dirt road) about 7 miles to the trailhead (about 8,100 feet elevation). Directions from the Fish Creek Trailhead to the summit of Grinnell Mountain:

From the parking area, hike trail southwest up the trail passing the junction with the Aspen Grove trail after about 1/2 mile. Keep left and continue 4 miles to Fish Creek Saddle at 9805'. Hike north on a use trail up the ridge to the summit. The hike is about 13 miles round-trip with 2,300 feet of elevation gain.