Located just a couple of miles north of Sonora Pass, Sonora Peak is the highpoint of Alpine Country, one of fifty-six California county highpoints in all. It divides no less than five different drainages (East Fork Carson River, Clark Fork Stanislaus River, Deadman Creek, Sardine Creek, and Wolf Creek), and despite being no more than a walk-up by virtually any route one could find, offers excellent views for very little effort. The Dardanelles are seen prominently in the west; panoramas to the north take in Stanislaus Peak and much of the Carson-Iceberg Wilderness, while views south include Leavitt Peak, Tower Peak, and in the distance, Mt. Lyell, Mt. Ritter, and Banner Peak.
As might be expected given the short approach, walk-up route, and outstanding views, this is a very popular summit. It makes an excellent introduction for peak bagging neophytes.
The peak is most commonly approached from trailheads along SR 108, although it could conceivably be reached as part of a longer backpacking excursion through the Carson-Iceberg Wilderness. The usual approaches are either from the St. Mary's Trailhead, located half a mile west of Sonora Pass, or from the Sonora Pass PCT trailhead. The St. Mary's Trailhead can be easy to miss (from both directions); it is best to drive slowly and look for a small sign on the north side of the highway. A sizable unpaved lot is found here (GPS coordinates: N 38° 20.23' W 119° 38.74'). Another unpaved parking area is found on the south side of the road, a short way east of the trailhead. Parking is also permitted along the road. Paved parking is found at Sonora Pass.
St. Mary's Pass. From St. Mary's Pass, located at the Carson-Iceberg Wilderness boundary, head east through meadows along a faint use trail to the ridge a few hundred yards north of the summit. The trail disappears in places, but becomes obvious once you gain the ridge; follow the ridge south to the summit. This route is class 1.
Pacific Crest Trail. From the Pacific Crest Trail, east of the peak, follow a use trail around and up the SE slope of the peak. A more detailed description for this route can be found in Pete Yamagata's Northern Sierra Peaks Guide.
Blissfully little compared to other areas in California. A wilderness permit is required for overnight camping in the Carson-Iceberg Wilderness, but this can be self-issued at the trailhead. Overnight camping is also permitted in the St. Mary's parking lot.
Due to the winter closure of SR 108, the peak is usually climbed during the summer/autumn months when the highway is open (typically May-Nov). It is reportedly a popular spring skiing destination when the Sonora Pass road first opens each year.
There are any number of developed Forest Service campgrounds along SR 108 in this vicinity, including Deadman, Upper/Lower Baker, Leavitt Meadow, and Sonora Bridge. Overnight camping is also permitted at the St. Mary's trailhead--at 9600 ft, perhaps a good choice for hassle-free acclimatization for higher peaks further south.
Further information may be found on the Stanislaus National Forest website.
Current highway conditions can be found on the Caltrans website.
Current snowpack information for the surrounding area can be found on the
CDEC Mokelumne/Stanislaus River Basin page. Deadman Creek (9250') is the closest station at which hourly data is collected. As an indication of the typical spring/early summer snowpack here, it might be worth mentioning that snow patches typically linger on the gentle slopes of the north side of St. Marys Pass (10,400ft) well into August/September even in light snow years.
Recent trail conditions may be found in the Stanislaus National Forest trailhead status report.
"The pass took its name from the town of Sonora, established in 1848 by Mexican miners from the state of Sonora. (Gudde, Place Names, 316-17.) The first printed record of the name 'Sonora Pass' is in the report of the Pacific Railroad Survey of 1853 under Lt. Tredwell Moore. This is shown on Goddard's map of 1857 as being about eight miles south of the present Sonora Pass, in the NW 14/ sec. 12, T. 4 N., R. 21 E. -- "Emigrant Pass" on the Tower Peak 15-minute quad. William H. Brewer was probably the first to use 'Sonora Pass' in reference to its present location, in 1863. 'July 17 we came on up the pass and camped at a little grassy flat, near the summit of Sonora Pass, at the altitude of 9,450 feet...' (Brewer, Up and Down, 423.) The peak probably was named by the Wheeler Survey; it is on atlas sheet 56D, 1878-79."
- Peter Browning, Place Names of the Sierra Nevada