Hidden Lake Trail

Hidden Lake Trail #745 is a steep out-and-back from the end of Sibley Creek Road to the historic lookout on Hidden Lake Peak. Published totals range from 8 to 9 miles round trip; the mapped trail corridor measures about 3.9 miles one way, so plan for the longer figure. Reported climbing also varies, from about 2,900 to 3,300 feet. Allow around eight hours with breaks. The reward is a real change of scenery: forest, flower meadows, high granite slopes, then a small lookout above the lake. The standard route ends at the lookout; reaching the lake shore takes a separate, off-trail boulder scramble below the saddle.

From Marblemount, follow State Route 20 to mile 106 and cross the Skagit River bridge onto Cascade River Road. After 10.2 miles, turn left onto Sibley Creek Road, Forest Road 1540, and continue 4.5 miles to the small trailhead lot. The gravel road is narrow, steep and rough, with washboards, ruts and few pullouts; a high-clearance four-wheel-drive vehicle is strongly recommended. Leave enough space for other vehicles to turn and get out. There is no toilet at the trailhead, and drinking water is not readily available, so bring what you need from the start.

The first mile climbs through forest, with runoff streams crossing or following the tread, before the trail crosses Sibley Creek. It then switchbacks up open avalanche slopes and flower meadows. This is the greenest part of the hike: look for cow parsnip, false hellebore and fireweed in season. The tread here has a history of slumps and mudslides, so stay on the main path rather than cutting through the flowers. A second, higher creek crossing opens a backward view toward Mount Baker.

After the second crossing, the grade eases for a while as the path winds among angular granite slabs, subalpine fir, heather and huckleberry. Little creeklets thread the slope, and the skyline opens to peaks including Mount Baker, Mount Shuksan and Eldorado. The meadow display is strongest in early summer; huckleberries ripen later. Near the summit, the trail turns into bare rock and a snow-holding gully. Sections of tread can disappear among rock and lingering snow, so keep track of cairns and visible trail. Snow can last into late summer; in early season, reaching the lookout may call for an ice axe, climbing experience and confident route-finding.

At roughly 6,500 to 6,600 feet, the saddle gives the first view of deep-blue Hidden Lake, tucked below the ridge, with Forbidden, Boston and Sahale peaks and Quien Sabe Glacier beyond. The lake can still have ice well into summer. The shore is a separate, steep half-mile boulder scramble each way with no trail; it is not part of the standard hike, and turning around at the saddle is a sensible choice. Pets may accompany hikers on leash to the lookout, but must not continue past the park boundary down toward the lake. An overnight stay on the park side requires a backcountry permit.

From the saddle, the lookout is about another half mile and 300 feet up a narrow, rocky path marked by blazes and cairns. Take your time on the broken slope; the cabin sits on a granite pinnacle and the trail is informal near the top. Built in 1931, it was retired from fire service decades ago and remains open to visitors through volunteer stewardship. Its wide summit view is the payoff for the climb; from the saddle, include the lake below with the peaks behind it, or at the top frame the small cabin against the surrounding ridges. The cabin is also used overnight on a first-come basis, so hikers planning to stay should be ready to share it.