Bumpass Hell Trail

View of Bumpass Hell boardwalk winding through thermal areas with grey and yellow thermally altered earth.

Start: Bumpass Hell parking area
Round Trip Distance: 3 miles
Round Trip Time: 2 hours
Terrain: easy 300 foot descent
Elevation: 8000 feet

The boardwalk and portions of the trail will be closed throughout 2018 for a rehabilitation project. Explore Lassen's other hydrothermal areas.

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4 minutes, 5 seconds

Learn more about the trail into Lassen's largest and most popular hydrothermal area, Bumpass Hell.


Trail Opening Information

The trail to reach Bumpass Hell is at a high elevation and recieves significant snowpack. Every spring, the trail will close due to severe winter hazards. On average, it opens by Fourth of July weekend each summer, however actual opening dates vary with each year's snow pack. For more information about Bumpass Hell trail status and conditions, please contact the visitor center (530) 595-4480.

Previous trail opening dates: July 13, 2011 | June 29, 2012 | June 25, 2013 | June 11, 2014 | June 7, 2015 | July 9, 2016 | August 22, 2017


Bumpass Hell is the largest hydrothermal area in the park, and marks the principal area of upflow of steam and discharge from the Lassen hydrothermal system (see illustration in photo gallery below). The temperature of high-velocity steam jetting from Big Boiler, the largest fumarole in the park, has been measured as high as 322°F (161°C), making it one of the hottest fumaroles in the world. The steam heated waters are typically acidic and are not safe, even for bathing. Please stay on the trail and boardwalks for your safety.


Last updated: January 20, 2018

Contact the Park

Mailing Address:

PO Box 100
Mineral, CA 96063


(530) 595-4480

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