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Trail difficulty
Elevation Gain
3,038.00 ft (925.98 m)
Trail type
17.50 mi (28.16 km)
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South Fork of the Boise - Headwaters Overview

The southeastern border of the Sawtooths is not well defined.  Some people consider the Alturas and North Fork of the Ross Fork drainages to be the boundary between the Sawtooth and Smoky Mountains. Others might draw the line along the divide between the headwaters of the Salmon and South Fork of the Boise River. Both definitions ignore the network of trails in the headwaters of the South Fork of the Boise. The North Fork of the Ross Fork, Johnson, Vienna, Emma, and Big Smoky Creek drainages can be connected into a variety of long loops that are best accessed from the Sawtooth Valley.

The canyons in the South Fork of the Boise are impressively deep with 2,000 to 3,000 feet of relief. The underlying geology, however, is predominately volcanic and sedimentary rock, so they lack the dramatic vertical walls found in the granitic heart of the Sawtooths. There are very few alpine lakes and cirques in the region. Instead, the broken rock tends to form long, sweeping slopes that drop steeply to the valley floor. Backpackers gravitate to the trails in the Sawtooth Wilderness, so these loops are more frequently explored on a motorcycle or mountain bike.

The trails in the South Fork of the Boise are steeper and less frequently maintained. The underlying geology erodes into loose, rocky conditions, and trails can deteriorate more quickly, especially in the steeper sections. Combine this with the remote location over the divide in the headwaters of the South Fork of the Boise and you have the ingredients for adventure (and possibly disaster!). Riders need to keep these factors in mind and take the necessary precautions to avoid getting stranded in this remote terrain.

Smiley Creek to Big Smoky "Loop"

The West Fork is used primarily by mountain bikers and motorcycle riders. With the construction of a new access trail from the Vienna Creek drainage, this great ride should get the attention it deserves. Big Smoky Creek is, however, a very remote drainage, so riders should plan accordingly before tackling this 18-mile route.  

A shuttle between the headwaters of Smiley Creek and the Salmon River trailheads is necessary and will require a total of 33 miles of dirt road driving by the end of the day. One way to shorten this is to leave a car at the mouth of the Salmon Headwaters and add 5 miles of mellow dirt road pedaling at the end of the ride.  Another option would be to split your group and travel in opposite directions, swapping cars at the finish. 

The trail can be ridden in either direction with a nearly equitable amount of downhill. Riding down the West Fork covers 8.3 miles of singletrack, while the clockwise option tallies 7.7 miles in two descents. The Big Smoky Creek section contains the most technical riding. This route is by far the best ride on the South Fork of the Boise trail network.

Reference: All content excerpted from Exploring the Sawtooths - A Comprehensive Guide by Idaho River Publications.

Logistics + Planning

Preferable season(s)




Parking Pass

Not Required


Fun, remote ride. Covers a lot of terrain. Wildflowers in late summer can be good.


Open to motorcycles. Remote and difficult terrain. Bad location for a mechanical issue. Long shuttle.

Pets allowed


Trailhead Elevation

7,580.00 ft (2,310.38 m)


Big vistas

Suitable for




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Our mission is to inspire adventure with beautiful, comprehensive and waterproof map-based guidebooks.  Owner, publisher, and photographer Matt Leidecker, grew up exploring and guiding on the rivers in central Idaho.  His award winning Middle Fork of the Salmon River – A Comprehensive Guide is the standard by which other river guidebooks are measured.  Printed on virtually indestructible YUPO paper, IRP guides are truly unique all-in-one resources for adventure.  Each book is loaded with full-color maps, stunning photographs, and information on the history, geology, and wildflowers.  Visit Idaho River Publications to explore our guidebooks to the Rogue River in Oregon and the mountains of Central Idaho.

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