Overview
Sawtooth Lake sits at 8,430 feet in a granite cirque at the foot of Mount Regan, the most distinctive peak in the Sawtooth Range. The lake is the largest in the Sawtooth Wilderness and arguably the most photographed, its deep blue water reflecting the sheer north face that rises more than 1,200 feet directly above the shoreline. The trail from Iron Creek Trailhead is 10 miles round-trip with 1,900 feet of elevation gain, a commitment that keeps casual visitors at lower elevations while delivering one of the finest alpine settings in Idaho to those who put in the work.
This is the most popular trail in Sawtooth National Forest, and the trailhead crowds reflect that status. Iron Creek Trailhead parking fills early on summer weekends, and the first few miles of trail see steady foot traffic from late July through Labor Day. The upper basin grows quieter as day hikers turn back, and the lakeshore itself has enough shoreline to find solitude even on busy days.
Check conditions before your visit through the Sawtooth National Recreation Area website or by calling the Stanley ranger station. Fire restrictions are common in summer and affect campfire opportunities for overnight visitors.
The Route
Miles 0 to 2.5: Iron Creek to the Wilderness Boundary
The trail begins at Iron Creek Trailhead (elevation approximately 6,570 feet) and follows the creek drainage southwest through lodgepole pine and Engelmann spruce forest. The gradient is gentle for the first 1.5 miles, making for an easy warm-up before the real climbing begins. The trail passes through the Sawtooth Wilderness boundary marker at roughly mile 1.5, where the forest transitions and the terrain opens slightly.
A signed junction at mile 2.5 points left toward Sawtooth Lake and right toward Alpine Lake. Stay left. This junction is where many hikers make their first stop to assess how they're feeling before committing to the steeper upper terrain.
Miles 2.5 to 4.5: The Climb into the Upper Basin
The trail steepens noticeably above the junction and begins switchbacking through open rocky terrain. Engelmann spruce gives way to whitebark pine, then to open granite slabs and boulder fields. The views open dramatically here, with the jagged ridgeline of the Sawtooths becoming visible to the west. Wildflowers fill the rocky meadows in late July, including Indian paintbrush, lupine, and penstemon.
A series of false summits characterizes this section. Each rise reveals another bench above it, which can feel discouraging for hikers unfamiliar with the terrain. The total gain from the junction to the lake is roughly 1,200 feet over 2 miles, steeper than the lower trail but manageable with a measured pace.
Miles 4.5 to 5.0: The Lake Basin
The trail crests a rocky shoulder and the lake suddenly appears below: a broad, blue-green expanse set against the vertical granite of Mount Regan's north face. A final descent of roughly 200 feet drops to the lakeshore, where flat granite slabs provide natural sitting and lunch spots.
The shoreline is roughly 1 mile in circumference and can be circled in about 30 minutes. The south shore provides the best views of the peak above. Water temperatures even in August rarely exceed 55 degrees Fahrenheit, but some hikers swim near the outlet.
When to Visit
July through September is the primary season. Most hikers find the trail fully accessible by late July in a normal snow year. August offers the most reliable conditions, with warm temperatures, clear mornings, and the best chance of avoiding snow on the upper approach.
Afternoon thunderstorms are common throughout July and August. Plan to reach the lake by late morning and begin the descent by early afternoon. The upper basin and Mount Regan's ridgeline attract lightning, and the exposed slabs above the treeline offer no shelter.
October sees a sharp reduction in visitors and brings cool, clear days well-suited to hiking. Snow can arrive in October and the lake basin often freezes by late October or early November.
What to Bring
Many hikers on this trail carry:
- 2-3 liters of water capacity (sources are available on trail, but the upper section can be dry late in the season)
- A water filter or treatment tablets
- Layers for wind and afternoon temperature drops above 8,000 feet
- Rain gear, given the frequency of afternoon thunderstorms
- Trekking poles, which reduce impact on knees during the descent over rocky terrain
- Sun protection, including sunscreen and sunglasses, as the upper basin reflects significant UV
Consider bringing microspikes or traction devices for early-season visits before the snowpack melts fully. Individual needs vary depending on fitness, experience, and conditions.
Practical Details
No permit is required for this trail as of 2026. Dogs are permitted but must be under control. The Iron Creek Trailhead has a vault toilet. Cell service is essentially absent from the trailhead and throughout the route.
The trail is well-marked with signs at all major junctions. The upper section has some informal use trails branching toward the base of the cliffs; stay on the main route toward the lake outlet. A good topographic map from CalTopo or Gaia GPS is worth downloading before you leave.
Understand Leave No Trace principles for the alpine environment: pack out all waste, camp well away from the lakeshore, and avoid trampling fragile vegetation on the rocky benches.
Getting There
From Stanley, drive west on Highway 21 approximately 3 miles. The signed Iron Creek Trailhead turnoff is on the left (south) side of the road. The parking area is about 0.5 miles down the access road. No high-clearance vehicle is required. Arrive early on summer weekends, as the lot fills by 8-9 a.m.
From Ketchum/Sun Valley, take Highway 75 north over Galena Summit (8,701 feet), then continue to Stanley and proceed west on Highway 21. Total drive time is approximately 1.5 hours from Ketchum.