Overview
Blue Lake sits at 11,300 feet in a rocky cirque beneath the north face of Mount Toll, one of the Indian Peaks summits that rises above the Brainard Lake basin. The lake's coloring - a vivid aquamarine produced by glacial flour suspended in the water - is the reason this trail appears on so many photographers' and hikers' bucket lists. On a calm morning, the lake reflects the dark granite cliffs above it and the sky, creating the kind of scene that looks too perfect to be real.
The trail is 5 miles round trip with 1,600 feet of gain, classified as moderate. That description holds for hikers with some mountain experience, though the high starting altitude at Mitchell Lake Trailhead (about 10,480 feet) means visitors arriving from near sea level should expect the thin air to affect their pace. The upper section of the trail above Mitchell Lake involves rocky terrain and some route-finding across boulder fields, but nothing requiring hands-and-feet scrambling.
No Indian Peaks Wilderness overnight permit is needed for this day hike, though the standard $15 Brainard Lake Recreation Area day-use fee applies. Before heading up, check current conditions for trail status and weather forecasts.
The Route
Miles 0 to 0.7: Trailhead to Mitchell Lake junction. The trail leaves Mitchell Lake Trailhead heading northwest through subalpine forest. The grade is gentle to moderate. At about 0.7 miles, a signed junction marks the split between the Mount Audubon Trail (left, continuing northwest) and the Mitchell Lake and Blue Lake route (right, turning more directly west). Take the right fork toward Mitchell Lake.
Miles 0.7 to 1.5: Mitchell Lake. The trail continues west through thinning forest and across meadow sections along Mitchell Creek. Mitchell Lake appears at around 10,700 feet - a smaller lake than Blue Lake above, but a pleasant setting with views up the valley toward the peaks. The trail skirts the southern shore of Mitchell Lake before climbing above it.
Miles 1.5 to 2.5: Rocky upper basin to Blue Lake. Above Mitchell Lake, treeline gives way completely to alpine tundra and then rocky terrain. The trail becomes less distinct in sections and relies on cairns to mark the route across boulder fields. The climb here is steeper than the lower section. At about mile 2.5, Blue Lake comes into view, its surface an almost unreal shade of blue-green against the grey granite of the cirque walls. Mount Toll rises directly to the south, and Paiute Peak is visible to the west.
The lake itself: The shoreline is rocky and open. Stay on established paths around the lake edge and avoid walking on the fragile alpine vegetation in the shallower soils near the water. There's good shelter from wind in some of the boulder groupings along the north shore.
Descent: Return the same way. The boulder field section above Mitchell Lake requires attention going downhill, as the rocks can be slippery when wet and foot placement demands care when legs are tired.
Permits and Fees
The $15 per vehicle Brainard Lake Recreation Area day-use fee (as of 2026) applies at Mitchell Lake Trailhead. An America the Beautiful pass does not waive this specific recreation area fee. No wilderness permit is required for day hiking this trail.
Overnight camping in Indian Peaks Wilderness requires a permit through Recreation.gov ($6 per group per night). There are no designated campsites at Blue Lake itself, and camping is restricted to specified zones within the wilderness. See our national forest camping permit guide for general guidance.
When to Hike
July through September is the main season. The trail above Mitchell Lake can hold snow into early July, and the boulder fields near Blue Lake may be icy with patches of hard-packed snow until mid-July in heavy snow years. The trail is at its most scenic in late July through early August, when wildflowers are at peak bloom in the meadows along Mitchell Creek.
September brings reliably smaller crowds than July and August, with stable morning weather and the first hints of fall color in the willows around the lake shorelines. Temperatures at the lake in September can drop into the 30s by late afternoon; carry warm layers regardless of the morning forecast.
Colorado afternoon thunderstorms: The upper basin is above treeline. Plan to be below treeline by 1 PM on summer afternoons. If storms are building in the west during your approach, make a conservative turnaround decision before reaching the lake. Lightning above treeline is a serious hazard.
What to Bring
Water: The Mitchell Creek drainage has water for filtering, but carry treated water from the trailhead. Many hikers bring 1.5 to 2 liters for this distance at altitude; individual needs vary. No water at the trailhead itself.
Layers: Even on warm summer days, the lake sits in a sheltered cirque that can stay cold and windy. A wind layer is worth having in your pack.
Sun protection: High UV exposure at 11,000 feet. Sunscreen, sunglasses, and a hat are standard.
Navigation: Download an offline map before leaving cell service. The trail is well-marked in the lower section but relies on cairns in the upper boulder fields. Phone GPS works without cell service when you have an offline map loaded.
Solid footwear: Hiking boots or trail runners with ankle support are better choices than casual shoes on the rocky upper terrain.
Altitude Note
Mitchell Lake Trailhead is at about 10,480 feet, which is already high enough to cause symptoms in some visitors. Blue Lake at 11,300 feet is higher still. Visitors arriving from sea level or low-elevation cities may experience headache, fatigue, or shortness of breath. Spending a night or two at a lower Colorado city (Denver at 5,280 ft, Boulder at 5,430 ft) before attempting this trail is a commonly recommended approach. Consult a physician if you have cardiovascular or respiratory concerns. Individual responses to altitude vary considerably.
Trailhead Access
Mitchell Lake Trailhead shares access with the Brainard Lake Recreation Area, reached via Brainard Lake Road from Ward, Colorado. From Boulder, the drive is about 40 miles and takes an hour. The road is paved to the recreation area entrance and gravel beyond. The parking area at Mitchell Lake Trailhead holds roughly 40 vehicles and fills quickly on summer weekends. Arrive before 7 AM on weekends for a reliable spot. Vault toilets are available at the trailhead.
For a longer day or a full summit experience from the same trailhead, the Mount Audubon Trail shares the initial section of trail before diverging at the 0.7-mile junction. The Pawnee Pass Trail from nearby Long Lake Trailhead offers a comparable alpine lake approach with a Continental Divide crossing for those wanting more distance.
Practice Leave No Trace principles in this heavily visited wilderness corridor. Stay on established trails, pack out all waste, and avoid picking wildflowers or disturbing the fragile lakeside vegetation.