Why Bumpass Hell Is the Signature Hike of Lassen
Bumpass Hell is the largest hydrothermal area in Lassen Volcanic National Park, a 16-acre basin of boiling mudpots, steaming fumaroles, and milky-blue pools fed by the still-active magma chamber beneath Lassen Peak. The trail is named after Kendall Vanhook Bumpass, a 1860s cowboy who broke through the thin crust and badly scalded his leg, then named the spot after the experience. Today a sturdy boardwalk keeps you safely above the bubbling ground, making this the must-do walk for any first visit to the park.
If you want to combine it with the rest of the park's highlights, see our full Lassen Volcanic day hikes itinerary, which pairs Bumpass Hell with Lassen Peak and Kings Creek Falls over two days.
Trail Stats and What to Expect
The hike is roughly 3 miles round trip with about 300 feet of climbing on the way out and a gentle descent into the basin. Most hikers finish in 2 to 3 hours including time on the boardwalk. The trailhead sits at about 8,200 feet on the Main Park Road, so the thin air makes the modest climb feel harder than the numbers suggest.
- Distance: 3 miles round trip
- Elevation gain: ~300 feet out, descent into the basin
- Difficulty: Moderate, mostly due to altitude
- Time: 2 to 3 hours
- Highlight: Boardwalk over boiling mudpots and fumaroles
Parking and the Trailhead
The Bumpass Hell parking lot is on the Main Park Road (Highway 89) between the Lassen Peak trailhead and Lake Helen, about 6 miles from the Kohm Yah-mah-nee Visitor Center at the southwest entrance. The lot fills early in July and August, so arrive before 9 a.m. or after 3 p.m. on summer weekends. If it is full, there is a small overflow pullout, but rangers discourage parking on the road shoulder. An alternate route reaches the basin from the Lake Helen area when the main lot is jammed.
Best Time to Hike and Snow Considerations
Because of its high elevation, the Bumpass Hell Trail is often buried under snow until mid-July, even in average years. The reliable window runs from late July through early October. Early in the season the first half mile can be icy and the boardwalk steps slick; check current conditions at the visitor center before you go. Late September brings crisp air, fewer crowds, and the best contrast between blue sky and white steam.
Safety on the Boardwalk
The ground around the hydrothermal features is thin crust over near-boiling water and acidic mud. Stay on the boardwalk at all times. Every year people are burned after stepping off to get a photo. Keep children within arm's reach, leave dogs at home (pets are banned on this trail), and do not let the steam fool you into thinking the pools are warm bath temperature; many exceed 200 degrees Fahrenheit. The smell of sulfur is strong but harmless in the open air.
What to Bring
Carry at least two liters of water, sun protection for the exposed ridgeline, and a light layer for the breezy overlook. Trekking poles help on the loose volcanic gravel of the descent. A telephoto lens lets you photograph the fumaroles without crowding the railing. Because the trail starts high, give yourself time to acclimate if you have just driven up from Redding or Red Bluff in the Central Valley.
Bumpass Hell Trail: Lassen's Largest Hydrothermal Hike FAQs
The hike is about 3 miles round trip with roughly 300 feet of elevation gain on the way out, taking most hikers 2 to 3 hours including time spent on the boardwalk.
Snow usually keeps the trail closed until mid-July. The reliable hiking window is late July through early October, so always check conditions at the Kohm Yah-mah-nee Visitor Center first.
Yes, as long as everyone stays on the boardwalk. The hydrothermal pools and mud exceed 200 degrees and the surrounding crust is thin, so keep children within arm's reach at all times.
