Square Top Lakes

Square Top Lakes are a pair of high-alpine tarns perched above 12,000 feet on the western flank of Guanella Pass in Clear Creek County. Sitting in open tundra directly beneath the imposing wall of Square Top Mountain (13,794 feet), these lakes offer one of the most accessible above-treeline hiking experiences along the Front Range corridor — and a welcome alternative to the crowded Mount Bierstadt trailhead right across the road.

The South Park Trail leaves from the Guanella Pass parking area and drops gently through a west-facing valley before climbing to a crest on the north valley wall. Lower Square Top Lake appears at 1.83 miles and 12,046 feet, and a marked spur continues steeply north to Upper Square Top Lake at 2.3 miles and 12,265 feet. The round trip covers roughly 4 to 5 miles with moderate elevation changes, making it manageable for fit beginners and families with older children. Expect the hike to take two to three hours at a comfortable pace.

Because the entire route sits above treeline, the scenery is nonstop. Summer visitors walk through carpets of alpine wildflowers — columbine, alpine sunflowers, and paintbrush — while pikas chirp from the surrounding talus and marmots sun themselves on boulders near the lakes. Fall brings golden tundra grasses and fewer crowds, and several reviewers call the autumn color display here one of the best along the Guanella Pass corridor.

The upper lake is the quieter of the two and a favorite spot for soaking tired feet after a summit attempt on Square Top Mountain or nearby Mount Bierstadt. Water temperatures stay frigid year-round at this altitude. Anglers occasionally try their luck, though the lakes are not heavily stocked and fishing pressure is light.

Parking is the main challenge. The Guanella Pass lot also serves the Mount Bierstadt trailhead, which is one of the most popular fourteener approaches in Colorado. On summer weekends, the lot fills before sunrise. Arrive early — ideally before 6 a.m. on Saturdays — or visit midweek to avoid the crunch. The pass is accessed via Guanella Pass Road, 11.8 miles south of Georgetown off Interstate 70 (Exit 228). Afternoon thunderstorms are frequent above treeline from June through September, so plan to be heading down by noon.