US-07 Aspen Pop

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The Four Pass Loop is Colorado’s premier alpine circuit — a 27‑mile journey over four high passes above 12,000 feet, wrapped around the iconic Maroon Bells. The route moves through wildflower basins, glacial valleys, red‑rock spires, and some of the most dramatic high‑country terrain in the Rockies. It’s a full‑value mountain odyssey: big climbs, big views, fast‑changing weather, and a sense of immersion that only the Elk Mountains can deliver. The Aspen Pop is a true high‑altitude epic — rugged, cinematic, and unforgettable.

• Location: Aspen, Colorado

• Distance: 29 miles

• Elevation Gain: 8,549 ft

• Estimated Time: 10–16 hours

• Route Type: Loop

The best time to hike the Four Pass Loop is July through September, when the high passes are mostly snow‑free and the alpine basins are at their most vibrant. Early July still holds lingering snow on the north‑facing slopes, while August and early September offer the most stable weather and the lowest risk of thunderstorms. By late September, cold nights and early storms start to return. For a safe, spectacular single‑day push, mid‑summer to early fall is the prime window.

All hikers need a **Maroon Bells access reservation** to enter the valley, even for a single‑day push of the Four Pass Loop. This reservation covers either a parking spot at Maroon Lake or a seat on the shuttle from Aspen Highlands during restricted hours. No wilderness permit is required for day use.

OFFICIAL RESERVATION LINK  

https://www.recreation.gov/timed-entry/10086910