Overview
Mount Zirkel at 12,180 feet is the highest summit in the Park Range and in the Routt unit of Medicine Bow-Routt National Forests. The Mount Zirkel Wilderness surrounds the peak with 160,000 acres of roadless terrain including lake basins, high meadows, and dense spruce-fir forest on the approach. The wilderness was first designated in 1964, one of the original wilderness areas established under the Wilderness Act. A major windstorm in October 1997 blew down roughly 6,000 acres of old-growth trees in the wilderness, and the blow-down areas are still visible along parts of the Slavonia approach, giving the route a ghost-forest character in some sections.
The Slavonia trailhead provides the most direct access from the Steamboat Springs side. The approach passes several lake basins that are worthwhile destinations in their own right, making this a good out-and-back even for hikers who turn around before the summit.
The Route
Miles 0.0 to 2.5: Slavonia to Wilderness Entry
The trail climbs from the FR-400 trailhead through old-growth spruce and fir forest, passing through some of the blow-down zones from the 1997 storm. Nurse logs and young spruce regeneration are visible in the affected areas. The wilderness boundary is crossed at mile 2.5 and the sense of remoteness increases.
Miles 2.5 to 5.0: Lake Basin to Summit Approach
Above the wilderness entry the route passes several high lakes with native cutthroat trout. The first lake appears around mile 3.0, tucked below the trail in a shallow basin. The summit approach begins in earnest at mile 4.0, where the gradient increases and the terrain transitions from forest floor to boulder fields. The last standing trees disappear before mile 4.5.
Miles 5.0 to 4.5: Summit Scramble and Turnaround
The mileage note in the original routing reflects the summit approach from the lake basin direction. The final half mile to the summit involves Class 2 boulder scrambling on stable but loose granite boulders. No technical equipment is needed under normal summer conditions. The 12,180-foot summit is marked with a register. The turnaround views north reach well into Wyoming; the Medicine Bow Mountains in Wyoming are visible on clear days, as is the full southern run of the Park Range toward Steamboat Springs.
Miles 4.5 to 9.0: Descent
Return the same route. The boulder section warrants careful footing on the way down, particularly if afternoon weather has made the rocks damp.
When to Hike
Late July through August for optimal conditions. Early season (July) may have substantial snow on the upper approach, particularly above the lake basins. Microspikes are worth carrying for July visits.
September the wilderness is at its quietest. The cutthroat fishing can be excellent in the lake basins in September. Early storms are a real possibility and can bring several inches of snow overnight. Carry winter emergency gear and be prepared for a rapid weather change.
What to Bring
Many hikers carry 3 liters of water for the full summit objective. Lake water on the approach can be filtered for resupply. Warm layers, a wind layer, and rain gear are standard for the exposed summit section where temperatures drop noticeably from the forest floor. Microspikes are useful in July for the upper snowfields. Trekking poles help with balance on the boulder section.
Trailhead Access
Slavonia trailhead at the end of FR-400 north of Steamboat Springs via CR-129. FR-400 is a rough gravel road; a high-clearance vehicle is helpful and may be required in wet conditions. No fee to park or hike (as of 2026). Vault toilet at the trailhead. Cell service is absent on this road; download maps and emergency contact information before leaving Steamboat Springs.
Nearby
Hahns Peak Summit Trail is in the same Park Range drainage and provides a shorter, lower summit alternative for a second day in the area. Big Creek Lakes Trail offers a lake loop near the Wyoming border for a lower-elevation contrast on days with uncertain weather.
Check conditions and trail snow status at checking conditions before you go. Practice Leave No Trace principles throughout the wilderness, particularly at the lake shores where camping should be 200 feet from water.