Timber Mountain (San Gabriel Mountains, California)

Timber Mountain

🏔️ Overview

Timber Mountain is an 8,303-foot (2,531-meter) summit in Southern California’s eastern San Gabriel Mountains. Rising above Icehouse Canyon within the Cucamonga Wilderness, the mountain is known for its conifer-covered slopes, quiet summit forest, and rewarding views toward Mount San Antonio, Telegraph Peak, Ontario Peak, and Cucamonga Peak.

The mountain is the southernmost of the famous Three T’s, a trio consisting of Timber Mountain, Telegraph Peak, and Thunder Mountain. Although it is the lowest of the three summits, Timber Mountain is often considered the most approachable. The standard route follows the scenic Icehouse Canyon Trail to Icehouse Saddle before joining the Three T’s Trail.

Unlike the exposed, pale summit of nearby Mount San Antonio, Timber Mountain remains wooded almost to its highest point. Its sheltered forest, steep final ascent, and proximity to several major San Gabriel summits make it a popular objective for hikers and peak baggers.

⚡ Fast Facts

Fact	Details
Continent	North America
Country	United States
State/Province	California
County/Region	San Bernardino County
Protected Area	Cucamonga Wilderness
Mountain Range	San Gabriel Mountains
Parent Peak	Telegraph Peak
Elevation	8,303 feet / 2,531 meters
Prominence	564 feet / 172 meters
Isolation	0.68 miles / 1.1 kilometers
Nearest Higher Neighbor (NHN)	Bighorn Peak
Coordinates	34.24509° N, 117.59361° W
USGS Topographic Map	Cucamonga Peak
Easiest Route	Icehouse Canyon and Three T’s Trail
Route Difficulty	Class 1 hiking

📍 Location

Timber Mountain stands in the Cucamonga Wilderness near the boundary between Angeles National Forest and San Bernardino National Forest. It is approximately four miles southeast of Mount San Antonio—better known as Mount Baldy—and immediately north of Icehouse Saddle.

The summit lies entirely within San Bernardino County, although it is close to the Los Angeles County line. The most frequently used access point is the Icehouse Canyon Trailhead along Icehouse Canyon Road, north of Mount Baldy Village.

Timber occupies a strategic position between several of the eastern San Gabriels’ best-known summits. Telegraph Peak rises to the north, while Cucamonga Peak and Ontario Peak stand across the deep canyons to the south and southwest.

📏 Elevation & Prominence

Timber Mountain reaches an elevation of 8,303 feet (2,531 meters). Its summit stands 564 feet (172 meters) above the mountain’s key col, which is approximately 7,739 feet in elevation.

This moderate topographic prominence gives Timber Mountain a recognizable summit while reflecting its close connection to the higher ridges around Telegraph Peak. Its isolation of only 0.68 miles also shows how tightly packed the high peaks are in this part of the San Gabriel Mountains.

Telegraph Peak is generally considered Timber Mountain’s parent peak, while Peakbagger identifies Bighorn Peak as the nearest higher neighbor. Parent peaks and nearest higher neighbors are related topographic concepts, but they are not always the same mountain.

🪨 Geology

Timber Mountain forms part of the eastern San Gabriel Mountains, a rugged section of the Transverse Ranges shaped by faulting, uplift, and rapid erosion. The wider range contains extensive granitic rocks alongside much older metamorphic and metasedimentary formations.

Much of the region’s granite originated from magma that cooled deep beneath the surface during the Mesozoic Era. Later tectonic movement uplifted these buried rocks, while erosion exposed them as the pale cliffs, broken ridges, and boulder-filled canyons seen today.

The eastern San Gabriels are especially steep because of their position near major fault systems, including the San Andreas Fault. Continuing tectonic uplift, earthquakes, wildfire, flash floods, and debris flows all contribute to the range’s rapidly changing landscape.

🌿 Flora & Fauna

Timber Mountain’s name reflects one of its most noticeable characteristics: its heavily wooded upper slopes. Mixed conifer forest surrounds much of the summit, creating a sharp contrast with the more exposed ridges of Mount San Antonio.

Ponderosa pine, Jeffrey pine, and big-cone Douglas-fir are characteristic trees of the Cucamonga Wilderness. Lower portions of the Icehouse Canyon route pass through chaparral, oak woodland, riparian vegetation, and shaded canyon forest before reaching the cooler high-elevation conifers.

Wildlife in the wilderness includes mule deer, black bears, mountain lions, squirrels, chipmunks, and numerous woodland birds. Nelson’s bighorn sheep also inhabit the rugged eastern San Gabriel Mountains, although sightings near busy trails are uncommon.

Hikers should never feed wildlife and should keep food secured. Bears generally avoid people, but food scraps and improperly stored supplies can attract them to campsites and rest areas.

🥾 Hiking & Climbing Routes

Icehouse Canyon Route

The standard hike begins at the Icehouse Canyon Trailhead at approximately 5,000 feet. The trail climbs steadily beside Icehouse Creek, passing old cabin foundations, shaded forest, and the junction with the Chapman Trail.

Hikers continue toward Icehouse Saddle, a major trail junction at roughly 7,580 feet. From the saddle, the Three T’s Trail heads north toward Timber Mountain. After approximately one mile, a signed spur leaves the main trail for the summit.

The final quarter-mile is considerably steeper than the preceding traverse. It climbs directly through the forest before reaching the broad, wooded summit area.

Depending on the exact route and mapping method, the hike is approximately 9 to 10 miles round trip with about 3,300 feet of elevation gain. Under dry conditions, it is a Class 1 hike, but its length, elevation, and sustained ascent make it strenuous.

The Three T’s Traverse

More ambitious hikers can include Timber Mountain in the complete Three T’s route. The classic traverse connects:

Timber Mountain
Telegraph Peak
Thunder Mountain

The route can be completed in either direction between Icehouse Canyon and Baldy Notch. A vehicle shuttle is commonly used because the trailheads are separated by road.

The traverse includes substantial climbing and descending between the summits. It also passes through exposed terrain where wind, heat, snow, or ice can make conditions considerably more difficult.

Approach from Telegraph Peak

Timber Mountain can also be reached from Telegraph Peak by following the Three T’s Trail south. From Telegraph, the round trip to Timber is approximately three miles, but hikers must regain significant elevation on the return journey. (Hundred Peaks Section Sierra Club)

🏔️ Field Guide Tip: Do not underestimate the final summit spur. Most of the route from Icehouse Saddle follows a moderate grade, but the last quarter-mile is steep. Save some energy for the final climb and the long descent through Icehouse Canyon.

Permits and Parking

A free wilderness permit is required beyond the Cucamonga Wilderness boundary. Permits may be available from the self-service box near the Icehouse Canyon Trailhead or from the Mount Baldy Visitor Center. Parking may require a valid recreation pass.

Regulations, fire restrictions, storm damage, and trail closures can change. Check current Forest Service alerts before leaving home.

Flower of the Manzanita, Arctostaphylos manzanita, in nature in California | Alessandra RC

🌤️ Best Time to Visit

Late spring through autumn generally provides the easiest hiking conditions on Timber Mountain. Snow may linger on shaded sections of Icehouse Canyon into spring, while autumn often brings cooler temperatures and clearer views.

Summer access is usually straightforward, but lower Icehouse Canyon can become hot during the afternoon. An early start helps hikers avoid the warmest temperatures and the busiest period at the trailhead.

Winter changes the nature of the hike completely. Snow and hard ice can cover narrow trail sections, especially after storms or during repeated freeze-thaw cycles. Proper traction, navigation equipment, winter clothing, and experience assessing mountain conditions may be necessary.

High winds are another important concern. Icehouse Saddle and the ridges around the Three T’s can experience powerful gusts even when conditions near Mount Baldy Village appear calm. (Modern Hiker)

🧭 Nearby Mountains & Attractions

Telegraph Peak

Telegraph Peak rises north of Timber Mountain and is the highest of the Three T’s. Its open summit provides wider views than Timber’s forested high point.

Thunder Mountain

Thunder Mountain stands near Baldy Notch and is the northernmost of the Three T’s. Ski-area roads and trails provide access from the Mount Baldy resort area.

Mount San Antonio

At more than 10,000 feet, Mount San Antonio is the highest summit in the San Gabriel Mountains. Its broad, largely treeless summit dominates views from Timber Mountain’s northern slopes.

Cucamonga Peak

Cucamonga Peak rises southeast of Icehouse Saddle. It is one of the most popular major summits reached from Icehouse Canyon and offers extensive views across the Inland Empire.

Ontario Peak

Ontario Peak stands southwest of Timber Mountain. Its summit route branches from the trail system near Icehouse Saddle and Kelly Camp.

Icehouse Canyon

Icehouse Canyon is an attraction in its own right. The lower trail passes beneath tall trees, beside a seasonal creek, and among the remains of recreational cabins dating from an earlier period of San Gabriel Mountain tourism.

💡 Fun Facts

Timber Mountain is the southernmost and lowest of the Three T’s.
The mountain’s wooded summit contrasts with the open, rocky crest of nearby Mount San Antonio.
The name “Timber Mountain” was used by local Sierra Club skiers and hikers by about 1930.
The name first appeared on the USGS Cucamonga quadrangle in 1953.
Timber Mountain appeared on the original Sierra Club Hundred Peaks Section list in 1946.
The standard summit route is almost entirely on established trails.
Some older summit registers and accounts have associated the mountain with the name Chapman, but the documented Timber Mountain name was already in local use during the early 20th century. (Hundred Peaks Section Sierra Club)

❓ Frequently Asked Questions

How high is Timber Mountain?

Timber Mountain is 8,303 feet (2,531 meters) above sea level. The figure is based on lidar elevation data and is more precise than the older 8,307-foot value appearing in some references.

Is Timber Mountain difficult to hike?

The standard route is technically straightforward Class 1 hiking, but it is physically strenuous. The round trip covers approximately 9 to 10 miles and gains about 3,300 feet.

What are the Three T’s?

The Three T’s are Timber Mountain, Telegraph Peak, and Thunder Mountain. A longer trail traverse connects all three summits.

Is there a trail to the summit?

Yes. The Icehouse Canyon Trail and Three T’s Trail lead to a short summit spur. The final quarter-mile is steep but normally easy to follow in snow-free conditions.

Is a permit required?

Yes. A free wilderness permit is required when entering the Cucamonga Wilderness beyond the marked boundary.

Are there views from the summit?

The immediate summit is forested, so views are partly obscured. Better viewpoints can be found by carefully walking toward openings along the northern side of the summit area.

Can Timber Mountain be hiked during winter?

It can be climbed in winter, but snow, hard ice, high winds, and poor visibility can turn an ordinary hike into a mountaineering trip. Winter visitors should carry appropriate equipment and have the skills to use it.

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