Overview
Mystic Island Lake sits in a cirque in the Eagles Nest Wilderness above Silverthorne, and the approach through the North Rock Creek drainage is one of the classic routes into this corner of the Gore Range. The round trip covers 7.6 miles and gains 1,800 feet, putting it in the moderate-hard category: a sustained hike that rewards fit hikers with a genuine high-alpine lake and the distinctive character of Eagles Nest wilderness terrain.
The Eagles Nest Wilderness covers roughly 133,000 acres of the Gore Range and surrounding terrain in Summit and Eagle Counties, straddling the White River National Forest. Most people know the wilderness through the Vail-side access points: Booth Falls, Pitkin Lake, Gore Creek. The Silverthorne-side approaches via the Blue River and Rock Creek drainages are less known, which means they're less crowded, especially on summer weekends when Vail trailheads fill by mid-morning.
The route follows North Rock Creek from the trailhead through a corridor of spruce-fir forest and aspen, climbing steadily through the drainage to the lake basin. Rock Creek is a productive fishery, and the trail crosses and recrosses the creek several times on the approach. In July and August, the drainage is one of the better wildflower areas in Summit County. In late September, the aspen groves on the lower trail turn gold.
Mystic Island Lake itself is set in a granite bowl, smaller and more intimate than some of the larger Eagles Nest lakes. The name comes from a small rocky island or partial peninsula in the lake's center. The surrounding peaks rise steeply on the south and west sides. This is not a summit hike; the lake is the destination, and the combination of the water, the rock, and the quiet makes it worth the effort.
The Route
Miles 0 to 1.5: Trailhead to North Rock Creek corridor. The North Rock Creek Trailhead is reached via Wilderness Road off CO-9 north of Silverthorne. From the trailhead and small parking area, the path descends to the creek level and begins following North Rock Creek upstream. The forest here is primarily Engelmann spruce and subalpine fir, with aspen appearing on south-facing slopes and in the broader sections of the drainage. The trail is clear and well-worn. The creek runs to the left of the trail and provides multiple places to filter water.
Miles 1.5 to 3.0: Steeper climbing and meadow sections. The trail steepens as the drainage narrows and the forest becomes denser. Several creek crossings occur on this section; most are straightforward rock hops in summer, but high water in early July can make them wet. The terrain alternates between forested sections and small open meadows where the creek widens into glades. These meadow clearings fill with wildflowers in July and August. The Gore Range peaks become visible above the drainage at the meadow openings.
Miles 3.0 to 3.8: Upper drainage and lake basin. Above 10,500 feet, the forest thins and the trail enters open rocky terrain. The route becomes less defined in places and relies on cairns. The creek is smaller and faster here, draining the upper cirque. The final approach to the lake crosses a short section of talus and a low ridge before the lake comes into view.
Mystic Island Lake. The lake sits at roughly 11,400 feet. The small island or rocky outcrop that gives the lake its name is visible near the center. The peaks of the Gore Range rise on the south and west sides, the highest summits above 13,000 feet. The north shore provides good access for fishing and lunch stops. The lake holds cutthroat trout and sees less pressure than lakes on the Vail side of the range.
Return by the same route.
When to Visit
July: The first viable month. The approach trail is typically snow-free by early July, but the lake basin may hold snow through mid-July. Wildflowers begin in the lower sections and peak in mid-July in the upper meadows. Afternoon thunderstorms are a daily possibility; start by 6 or 7 AM to be back below the upper basin before early afternoon.
August: Strong month for wildflowers in the first half and for the overall hiking experience. The basin is fully accessible. Thunderstorm timing is aggressive in August, sometimes developing by mid-morning in the Gore Range. Early starts are non-negotiable on this hike.
September: The best month by most measures. Crowds drop immediately after Labor Day. The aspen groves on the lower trail turn gold in mid-September, and the light in the basin on clear September mornings is exceptional. Temperatures at the lake can drop to freezing or below at night. Afternoon weather is more stable than in July and August, but snow is possible at lake level by late September.
October: The lower trail remains accessible and the aspen color can extend into mid-October. Snow in the upper basin makes the final approach uncertain; check conditions before attempting.
Practical Details
Parking: Gravel lot at North Rock Creek Trailhead. No fee, no pass required. Pit toilet on site. The lot holds 15 to 20 vehicles. Summit County trailheads fill on summer weekends; arrive by 8 AM for a space.
Permits: None. The Eagles Nest Wilderness has no permit quota system as of 2026.
Dogs: Allowed on leash. The creek crossings and rocky upper terrain are manageable for most dogs. Bring water; the creek provides multiple access points in the lower and middle sections.
Fishing: North Rock Creek and Mystic Island Lake hold cutthroat trout. A Colorado fishing license is required.
Altitude: Trailhead elevation is approximately 9,600 feet, the lake approximately 11,400 feet. The elevation gain is moderate relative to the starting elevation, but the starting altitude is significant. Allow time to acclimatize in Silverthorne (9,035 feet) before attempting the hike.
Water: North Rock Creek provides water throughout the lower and middle sections. Filter before drinking. Carry 2 to 3 liters.
Camping: Permitted in the wilderness. Camp on durable surfaces at least 200 feet from water, following Leave No Trace principles. No campfire rings in the upper basin; use a stove.
Getting There
From Silverthorne (approximately 8 miles, 20 minutes): Take CO-9 north from Silverthorne toward Heeney. Watch for Wilderness Road on the right (east) side of CO-9. Turn onto Wilderness Road and follow it to the North Rock Creek Trailhead. The road transitions from paved to gravel; it's passable by standard vehicles.
From Frisco (approximately 10 miles, 20 minutes): Take I-70 east to Exit 205 (Silverthorne/Dillon), then north on CO-9 as above.
From Denver (approximately 80 miles, 1 hour 30 minutes): Take I-70 west to Exit 205 (Silverthorne/Dillon), then north on CO-9.
Silverthorne has full services: gas, grocery stores, restaurants, and outdoor gear shops at the outlet mall area. Fill up before heading north on CO-9.
The Bottom Line
Mystic Island Lake is the better-kept secret of the Eagles Nest Wilderness. The Silverthorne approach through North Rock Creek is longer and slightly more work than some of the Vail-side routes, but the reduced crowds are a meaningful benefit, and the creek corridor itself is one of the better drainage walks in Summit County. For hikers ready to step beyond Silverthorne's easier trails and into the real Eagles Nest, this is the right place to go. The Maroon Bells Scenic Loop near Aspen offers an easy complement for a multi-day White River itinerary, while Grizzly Lake on the Independence Pass road provides a no-permit Aspen-area alpine lake at comparable difficulty. On the Aspen side of the White River National Forest, the Lost Man Loop near Independence Pass is another no-permit high-country option that pairs well with a Silverthorne-based trip. From Denver, the I-70 approach to Silverthorne is one of the most efficient access points in the White River National Forest. The best hikes near Denver guide covers this trail and the full range of Eagles Nest Wilderness approaches.