Conundrum Hot Springs

Conundrum Hot Springs is a natural pool at 11,200 feet at the head of Conundrum Creek, 8.5 miles from the trailhead outside Aspen, and the most sought-after backcountry campsite in Colorado. The walk in is long and gentle with three creek crossings, the pool holds a dozen people at about 100 degrees, and the overnight permits required since 2018 sell out within minutes of release. Day hiking the 17 miles is legal and long.

From the Conundrum Creek trailhead at about 8,800 feet, the trail follows the creek south up a broad valley of aspen, meadow, and spruce, gaining elevation so gradually that the first 5 miles feel flat. The creek is crossed three times, on bridges or logs that wash out some years; the crossings are the wet part of the day in June.

The valley narrows and steepens in the last 3 miles, climbing through spruce and past avalanche debris to the campsites and the springs at 11,200 feet, with Castle Peak's ridges above. The main pool is the big one; a smaller pool sits below it. The trail continues over Triangle Pass toward Crested Butte for a point-to-point trip. Return the same way.

From the roundabout on Highway 82 west of Aspen, take Castle Creek Road 5 miles south to Conundrum Creek Road, then about 1 mile to the trailhead lot. Parking is prohibited along Conundrum Creek Road, which crosses private property, and the Forest Service says vehicles left on it will be towed; if the lot is full, come back another day. The Colorado Mountain Club notes that the area can be closed for elk calving from mid-May through June, so check the Aspen-Sopris Ranger District before a spring trip. Overnight permits for the Conundrum Hot Springs zone are required year-round, reserved on Recreation.gov, released in advance for the season, and gone within minutes for summer weekends; each permit names a designated campsite. Day hikers need no permit. The lot is small; the road is gravel and fine for passenger cars.

No dogs in the Conundrum zone, a rule the Forest Service enforces, which is why the record shows no dogs. Not a kid trip. Overnight visitors must carry an IGBC-approved bear canister big enough for all scented items and pack out human waste in a bag, both required by the permit. Groups are capped at 10, and each designated campsite has its own limit of 2 to 6 people. Camp only at the site on the permit. No soap, no glass, and no alcohol in the pool; clothing has been optional here for decades and the etiquette is to not photograph strangers. Carry a filter; the creek is the water. Aspen has the gear shops. The Conundrum guide covers the permit lottery, and the Aspen hikes page has the day hikes.