Osberg Ridgeline Trail #147:
The trail has a seasonal designation for motorcycle and e-bike use and is open to those uses from May 1 to August 29 of each year.
Originally built by the Civilian Conservation Corps in the 1930s, and known then as the Warm Springs Ridge Trail, it was rebuilt and renamed the Osberg Ridgeline Trail after Gloria Osberg, a longtime conservationist and author of "Day Hiking Near Sun Valley."
Just before the 2013 Beaver Creek Fire broke out this ridge line trail underwent a transformation. The route was reconfigured and rebuilt in 2012 and 2013 by the Ketchum Ranger District. In its former incarnation as the Warm Springs Ridge Trail the route was mostly known as one to be avoided. Some horseback riders and motorcyclists enjoyed the trail, but many a motorcyclist and equestrian swore it off after one passing. The trail took very direct lines as it traversed the ridge lines between the Baker and Warm Springs drainages. In 2012 and early 2013 the Ketchum Ranger District and its partners rebuilt the trail and rechristened it the Osberg Ridgeline Trail #147. The new route was a nicely graded, yet challenging, 12-mile trail that traversed along the divide at around the 9,000-plus-foot mark.
Unfortunately, the newly reshaped trail was only available for the public's enjoyment for a short while, as the Beaver Creek Fire soon consumed the new singletrack. Despite its short-lived life, the rerouted trail received high praise from the trail using public. Mountain bikers were especially fond of it, and the many options for longer rides it opened up.
The Ketchum Ranger District has again rebuilt the trail.
The trail follows the ridge on the south side of the Baker Creek drainage north of Ketchum. It begins at the Baker Lake Trailhead, eight miles up, and at the end of Baker Creek Road. The trail makes connects to the Castle Creek, Barr Gulch, Alden Gulch, Rooks Creek, Fox Peak and Adams Rib trails.
In the 2012 and 2013 rebuilding of the trail the work was conducted under the direction of the Ketchum Ranger District trails staff. Four 12-person Northwest Youth Corp crews spent about two and a half months camping in the backcountry and providing the bulk of the hand labor to reconstruct the trail. The Idaho Department of Parks and Recreation and the Forest Service provided two small trail mini-excavators and two equipment operators toward the project on sections of the trail that could be accessed with machinery.
Volunteers from the Idaho Trails Association helped to complete the 2012/2013 work. About half the work’s $160,000 cost was funded by a grant from the Idaho Department of Parks and Recreation, and about 20 percent came from the Forest Service. The remainder of the funding was supplied by donations gathered by the Wood River Land Trust and the Idaho Conservation League.
The 2015 reconstruction of the trail was carried out by hand. The work was performed by the KRD Trail Crew and youth crews from the Northwest Youth Corp.
Directions: Head north on Highway 75 to Baker Creek Road/Forest Rd. #162 (15.4 mi). Turn left/west and stay on the main dirt road for approximately 10 miles to its end at the Baker Lake Trailhead. The signed Osberg Ridgeline Trail starts near the east end of the parking area; east of the vault toilet and near a big stump.
*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.