This 19.2-mile out-and-back climbs to the headwaters of Loon Creek, a cascading tributary of the Middle Fork of the Salmon. You’ll pass trout-choked waters and a lonely creekside hotspring as you cut through the largest wilderness in the Lower 48 (2.4 million acres!).
The start is tricky: Walk west past the Loon Creek Guard Station (about 50 miles northwest of Sun Valley Ski Resort) to a horse pasture out back. At the fence line, angle southwest to a gate at the far end of the field. Leave the gate as you find it (open or closed), and hike .6 mile through meadows and mixed pines and firs to the Trail Creek Trail.
Bear left to go 1.8 miles through streamside willow thickets and the remains of a decades-old burn before arriving at another junction at mile 2.4. Bear right and drop steeply to a ford of brush- and boulder-lined Pioneer Creek, a rager through late June that you can wade or cross on downed logs come late summer.
From here, hike a half-mile to a knee-deep ford of Loon Creek before stopping for a break at a rock-lined hot spring (big enough for three or four) on the opposite shore at mile 3.7. Continue upstream, and in .8 mile you’ll arrive at the spot where the author came face-to-face with a gray wolf, whose haunting howls bounced off the granite canyon walls. Press on through lodgepole pine- and aspen-filled avalanche chutes to another ford at mile 5.3 and a final ford in another 1.9 miles.
In .8 mile begin the final push, gaining 840 feet in 1.6 miles. The trail levels out at ponderosa-lined Horseshoe Lake; several campsites come into view at mile 9.6. The best is midway along the west shore, directly across from a forested peninsula that creates the lake’s namesake horseshoe shape. Return the way you came.
Contact: Call Challis-Yankee Fork Ranger District for the latest conditions: (208) 879-4100.
Gear Up: Riverwear Sports; ID 21, Stanley, Idaho; (208) 774-3592; riverwear.com
-Mapped by Jason Kauffman