Adams Gulch is the busiest trail system near Ketchum, and the Forest Service calls its trailhead the most popular on the Ketchum Ranger District. The network spreads across the main gulch and several side drainages on the Sawtooth National Forest just north of town, with roughly 33 miles of trail by one count. Mountain bikers, trail runners, hikers, horse riders and dog walkers all use it, and it is close enough to ride to from downtown. Idaho Mountain Express readers voted it the best mountain biking trail in the valley in 2020.

From Ketchum, drive about 1.5 miles north on Highway 75, turn left on Adams Gulch Road, go about three quarters of a mile, turn right after the bridge and then left into the trailhead. There are vault toilets and an interpretive sign, but no water and no overnight camping. You can also ride from town on the bike path along the highway, or come over the Heidelberg Hill trail from Warm Springs Road. The lot fills on summer weekends.

The easy trails are Shadyside, Trail 317, about 1.7 miles, and Sunnyside-Lane's, Trail 316, about 2.5 miles. They run on opposite sides of the gulch and can be combined into a short loop, and Lane's ends at a picnic table with a view down the valley. The first two miles of Old Adams Gulch Road, Trail 146, up the canyon floor are also easy. Citizens Trail, Trail 143, is a 1.1-mile connector. Loops of about three, five and six miles can be built from the main gulch trails.

The classic intermediate ride is the Griffin Butte loop. MTB Project measures it at 6.8 miles with about 1,270 feet of climbing: up Trail 146, onto Trail 177 and the Griffin Butte Connector, Trail 839, to the saddle on Adams Rib, Trail 142, then down the Pork Chop section of Adams Rib and out on Sunnyside. The Forest Service lists the loop at 7.6 miles. It can be ridden in either direction and has views of the Pioneer Mountains. Harper's Trail, Trail 323, about two miles, is often linked with the connector toward Lake Creek, and a longer intermediate loop that strings together Harper's, the Adams loops, Griffin Butte, Eve's Gulch, Forbidden Fruit and Shadyside runs about 11 miles with close to 1,900 feet of climbing.

The harder trails sit higher up. Eve's Gulch, the upper five miles of Trail 146, is rated most difficult, and Adams Rib above the saddle is rough and rocky. Forbidden Fruit, Trail 159, is a 1.1-mile one-way downhill trail for mountain bikes only, with berms and tabletop jumps that can all be rolled. The Wood River Trails Coalition helps maintain it. Hikers and runners should stay off it, and riders should slow down at the bottom where it meets Eve's trail. The Forest Service has worked on that junction because riders were coming off Forbidden Fruit too fast. Forbidden Fruit is the only one-way, bike-only trail in the system. Everything else is two-way and shared.

Motor vehicles, e-bikes included, are banned on every trail here except Old Adams Gulch Road and Eve's Gulch, Trail 146. The Forest Service brochure lists that route as open to motorcycles and e-bikes from May 1 to August 29, so expect some motorized traffic there in summer.

The 2007 Castle Rock Fire sent a spot fire into the upper gulch, and parts of the Griffin Butte loop still pass through burned timber. The south-facing Sunnyside side dries out first in spring. Lupine lines Sunnyside in early summer, wildflowers peak around mid-July, and the aspens turn in late September.

Dogs must be leashed within 200 feet of the trailhead, and owners must pick up waste. Past that, the Blaine County Recreation District asks that dogs stay under voice or leash control, and many people let their dogs run on the trails. Bikers yield to hikers, runners and horses. With this much traffic, slow down on blind corners and expect dogs and kids on the lower trails.

Fox Creek Loop and Lake Creek are a few miles north, and the Warm Springs side of town is reached over Heidelberg Hill.