Bumpass Hell Trail

Overview

Bumpass Hell is the park’s signature hydrothermal hike: a short, high-reward out-and-back that delivers you to a boardwalk threading through boiling pools, mud pots, and hissing vents. The hike is about 3.0 miles total (round trip) with roughly 439 feet of gain. Expect a strong sulfur smell in places and an experience that’s equal parts geology lesson and photo op.

What You’ll See

From the trailhead, you traverse a mountainside with big alpine views before descending into the basin. Down on the boardwalk you’ll pass vividly colored pools, roiling mud pots, and steaming fumaroles. There are interpretive stops that explain how this active volcanic system works, and summer often brings a nice show of wildflowers along the approach.

Route and Difficulty

The path is well maintained and generally easy to moderate. You’ll climb gently to an overlook, then drop more steeply into the basin; you’ll re-climb that descent on the way out. At around 8,000 feet, the altitude can make the return climb feel spicier than the stats suggest. Benches along the route help with pacing. Typical hiking time is about 1 to 1.5 hours, but linger longer on the boardwalk if conditions are comfortable.

Safety and Etiquette

Absolutely stay on the trail and the boardwalks—the ground can be thin and brittle with scalding water just below the surface. The area’s namesake, Kendall Bumpass, was badly injured after breaking through the crust in the 1800s. Expect sulfur (“rotten egg”) odors; move along to clearer air if needed. Wear sturdy shoes; the short, steeper section into and out of the basin can be dusty. Pets are not allowed on park trails or boardwalks.

Best Time to Hike

This is a high-elevation trail that typically remains closed through spring and often into early summer. It most often opens by mid-July (in 2025 it opened July 21), but exact dates vary with snowpack. When it’s open, start early for cooler temps, easier parking, and lighter crowds. Morning and late afternoon offer softer light on the basin’s colors; midday brings harsher light and more people.

Planning Tips and Alternatives

No day-use permit is required for this hike; standard park entrance fees apply. There are restrooms near the trailhead. The park does not operate a shuttle. If Bumpass Hell is closed or jammed, consider Sulphur Works (a roadside hydrothermal area) or the Warner Valley hikes to Boiling Springs Lake, Devils Kitchen, or Terminal Geyser for more hydrothermal exploring.