0.0 star · Extra Difficult Out and Back

Thunder Lake Trail

Boulder County, Colorado

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Trail length

21.0 km

Time

~1 day 0 hrs

Elevation Gain

742 m

"An epic challenge to remember from the heart of Boulder County"

The Thunder Lake Trail is a 21.0 km looped trail that starts and ends in Allenspark, Boulder County, Colorado. Based on our data, the trail is graded as Extra Difficult. For information on how we grade trails, please read measuring the difficulty of a hiking trail on hiiker. Also, check our latest community posts for trail updates.

This trail can be completed in approx 2 days. Caution is advised on trail times as this depends on multiple variables. For more info read about how we calculate hike time.