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Greenhorn Trail #156
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Status: Closed
Difficulty: Advanced
Uses: Mt Biking & Hiking & Equestrian & Motorcycle
Length: 8.96 miles
Start: 5,894'
End: 8,365'
Min: 5,874'
Max: 8,540'
Gain: 3,476'
Loss: -1,017'
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Trail Info
Thank you area motorcyclist volunteers and the Ketchum Ranger District Trail Crew for the many passes you have made cutting out, and re-cutting out, the trails in Greenhorn and beyond! Much of the Greenhorn drainage area burned in recent fires, so trees can come down at any time. Keep that in mind as you plan your outing and allow for extra time. For your safety, avoid burned areas if threatening weather is forecast.
Trailhead Forecast
Description / Access Information
Greenhorn Trail #156: Cut-out most recently in early July by motorcyclist volunteers with Idaho Mountain Dirt Riders Association. The creek crossing near the trail's intersection with the Mahoney Trail is rather tricky. The channel in the middle is pretty deep and steeply sided.

Great for an out-and-back or to use as part of one or more loops that branch off of the trail. The trail departs the trailhead to the south and crosses Greenhorn Creek over a series of footbridges as it meanders up the drainage. A very long trail that gets very demanding and can be taken for about 9 miles to the head of the canyon at Mars Ridge.

Much of the Greenhorn Gulch drainage burned in recent fires, but the trails in the area are on the rebound. Repair and restoration efforts by the Forest Service, Wood River Bike Coalition, Wood River Land Trust, and other partners and volunteers for the Ketchum Ranger District were carried out during the summer of 2014. The trails were reopened after an intensive season of rebuilding.

The trail crosses through a pleasant patchwork of riparian vegetation and aspen trees before climbing through dense pine and fir forest to a high ridge. The views of the Pioneer Mountains from the top are outstanding.

Loops are possible via the Imperial and Mahoney trails, or by using this trail as part of deeper explorations to places like the rather distant Mars Ridge region.

The Greenhorn Gulch drainage, which includes Cow Creek, Lodgepole Gulch, Mahoney Gulch, Greenhorn Creek, and Imperial Gulch has the highest concentration of multi-use trails in the valley.  Much of the northern half of the drainage was burned quite severely during the Castle Rock Fire in 2007. A lot more of the area burned intensely during the 2013 Beaver Creek Fire.

Use extra caution when planning outings in areas impacted by the recent fires. Storms can create flash floods, debris flows, and falling timber. Check the weather and keep your eye on the skies when you are headed out for a hike or ride. Travel is not recommended in burned areas when threatening weather conditions exist. Burned, standing trees can come down in any weather, but when windy conditions develop the situation becomes especially dangerous. When in doubt stay out.

The trails in the drainage pass through a wide variety of terrain. They pass through dense forest, open grasslands, flower-covered slopes, meandering ridgelines and, more recently, burned and limbless forests recovering from the fire. The interconnected nature of the Greenhorn trails allows for a wide variety of loops as all of the drainages are linked along the western divide.

For hikers, some of the available loops may be longer than they might wish to cover in a day. However, there are several shorter options between the Cow Creek and Mahoney Gulch trails.  Out-and-back hikes are also a great option on both the Greenhorn and Imperial Gulch trails.

Please keep in mind that all of the trails in Greenhorn Gulch are multi-use and open to motorcycles, and the motorcycle community stays involved in the maintenance of the trails. They help make possible the prompt opening of the trails by cutting out the vast majority of the downed trees that litter the trails each spring. Its also good to keep in mind that through the purchase of the State of Idaho's Off-Highway Motor Vehicle Use sticker fees, the motorized community is instrumental in the funding for many of the trail improvements on our shared-use motorized trails. In the late '70s and early '80s funds for the development of many of the trails in Greenhorn came from such fees.

From Ketchum, head south on Highway 75, or the paved Wood River Trail, for 5.5 miles to the Greenhorn/East Fork Road at the stoplight. Head right/west for 3.7 miles to the end of the Greenhorn Road at the FS Greenhorn Trailhead.

From Hailey, head north on the highway or the path. Its 5.5 miles to the Greenhorn/East Fork Road at the stoplight. Head left/west for 3.7 miles to the end of the Greenhorn Road at the FS Greenhorn Trailhead.

The Greenhorn Trail #156 heads south from the parking area, crosses the creek over two footbridges and then bends west to continue up the drainage.

For more detailed descriptions, topo maps, and information on the history, geology, and wildflowers of the Wood River Valley pick up a copy of Exploring Sun Valley online or find it at one of several local shops.
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