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Twin Sisters Trail

Six Rivers National Forest, California · 3 min read

Distance
6.5 mi
Elevation Gain
2,500 ft
Difficulty
strenuous
Route Type
Out-And-Back
Best Season
July through September
Dog Friendly
Yes
Difficulty Score
10 / 10

Trailhead Amenities

Restroom
None
Parking
No Lot
Cell Service
No Signal
Water
Nearby
Camping
Dispersed
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Conditions, regulations, and fees change frequently. Verify with the local ranger district before your trip. Full disclaimer

At a Glance

  • Twin Sisters peaks in the Siskiyou Wilderness, with views of the Klamath Mountains
  • Serpentine soil plant community with rare endemic species
  • Brewer spruce, an ancient tree species found only in the Klamath Mountains
  • Remote wilderness with essentially no other hikers
  • Views toward Redwood National Park and the Pacific Ocean

Overview

The Twin Sisters Trail climbs to the most dramatic summit in the Siskiyou Wilderness of Six Rivers National Forest, passing through one of the most botanically extraordinary landscapes in North America. The 6.5-mile round trip is strenuous but delivers: the serpentine soil plant community on the upper slopes contains endemic species found nowhere else on earth, including the ancient and unusual Brewer spruce, and the summit views across the Klamath Mountains are among the finest in northwestern California.

No permit required.

The Route

Miles 0 to 2.0: Forest approach. The trail climbs through Douglas fir and tanoak in the lower sections. The forest is rich and dense, typical of the moist Klamath Mountain environment. Seasonal streams provide water in early season.

Miles 2.0 to 3.25: Serpentine transition. The trail crosses onto serpentine bedrock and the vegetation changes dramatically. The dense forest opens to a sparse, almost otherworldly plant community: low, twisted conifers including Brewer spruce, Jeffrey pine, and foxtail pine on the rocky slope. The ground vegetation is sparse and often unfamiliar. This is the most botanically interesting section.

Summit area. The Twin Sisters peaks provide 360-degree views: the Pacific Ocean to the west, Redwood National Park visible in the coastal haze, the Klamath Mountains spreading in all directions, and the Trinity Alps to the south.

When to Hike

July through September after snowmelt on the upper serpentine.

What to Bring

Many hikers carry 2 to 2.5 liters of water. Trekking poles for the steep ascent. Wind layer for the exposed summit.

Trailhead Access

Forest Road 18N07 from US-199 east of Gasquet.

Practical Details

No permit is required for day hiking on this trail. Dogs are welcome on leash. No restroom facilities are at the trailhead; plan accordingly. Water sources are present along the trail but require treatment before drinking. No cell service is available in this area; download offline maps before leaving the main road.

The recommended season for this trail is July through September. Conditions outside this window may include challenging weather, trail closures, or reduced accessibility. Always verify current conditions with the Six Rivers National Forest ranger district before visiting, particularly at the beginning and end of the recommended season when conditions are most variable.

Before any visit, review the Leave No Trace seven principles and our checking conditions guide for current fire restrictions, trail closures, and ranger district advisories. The America the Beautiful pass covers day use fees at developed recreation areas where applicable. Veterans and active military have additional access options covered in our veteran benefits guide.

Nearby

The Smith River National Recreation Trail in the same Del Norte County area provides an easy riverside complement. See the Six Rivers National Forest guide. Follow Leave No Trace principles in the fragile serpentine plant community.

Trailhead Parking

Twin Sisters Trailhead on Forest Road 18N07, east of Gasquet in Del Norte County. Gravel road, high-clearance required. Small lot. No fee.

← Back to Six Rivers National Forest

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Frequently Asked Questions

What makes the Siskiyou Wilderness botanically significant?
The Siskiyou Wilderness sits on serpentine and ultramafic soils that are toxic to most plants. The few plants adapted to these soils have evolved in isolation over millions of years, resulting in a high rate of endemic species found nowhere else. Brewer spruce (also called Weeping spruce), which grows only in the Klamath Mountains, is found here along with numerous rare and endemic species. The botanical diversity per acre in the serpentine areas of the Siskiyou wilderness is among the highest in North America.
How strenuous is the Twin Sisters Trail?
The Twin Sisters Trail is the most demanding hike described for Six Rivers National Forest. The 6.5-mile round trip gains 2,500 feet with steep sections throughout, particularly in the final push to the summit area. The trail is well-maintained but rocky and exposed above treeline. Hikers should be in good physical condition and have experience with sustained steep climbing. The reward is one of the best views in the Klamath Mountains.
Is there water on the Twin Sisters Trail?
Seasonal streams are present in the lower forested sections of the trail, typically reliable through July. The upper serpentine sections have no reliable water. Carry at least 2 liters from the trailhead. If using creek water in the lower section, filter or treat before drinking.