About the Site
Lassen Volcanic National Park (9)  


Park History

Lassen Peak

Lassen Peak Summit

Chaos Crags

Manzanita Lake



Park Mountains

Sulphur Works

Volcanic Remnants

Southwest Area

Park Road


Plants & Animals


Sulphur Works

The smell of hydrogen sulfide, like rotten eggs, greets visitors as they proceed north on the main park road and approach Sulphur Works. At about a 7000 foot altitude, Sulphur Works is one of the primary geothermal areas within the park. The name is derived not only from its smell but also from historical efforts to mine sulphur from the area. Sulphur Works was also known as "Supan's Springs" after the original owner who ran the mining operation.

The upper section of Sulphur Works includes a .10 mile boardwalk trail, which is seen in the photograph below. Mount Diller can be seen in the Background.

Sulphur Works features fumaroles, mudpots, hot steam, boiling water, and other geothermal features, including the ever-present hydrogen sulfide gas. The surface is composed of andesite rock.

In areas rich in geothermal features, such as Sulphur Works, pools of hot water exist when there is sufficient ground water. When the amount of water diminishes, mudpots present themselves, and dry vents exist as fumaroles.

At Sulphur Works gasses bubble up through hot mud.

Sulphur Works is located near the very center of the ancient Mt. Tehama. It is actually a remnant of the central vent of the mountain. The summit of that peak, when it existed, was located about 4000 pounds above the current location of Sulphur Works.

The Sulphur Works area has a colorful history. The rights to it were purchased by Mathias B. Supan in 1865, and it was first mined for sulphur in 1866, but the endeavor did not prove profitable. Supan later offered tourist amenities at the site, including hot mineral baths. Supan's son, Mathias, in 1927 began construction of a gas station and tourist facilities on the site. By 1941, there was a gas station, lunchroom, a bathhouse, and a large dining room known as "The Sulphur Works Inn."

The government was determined to include the Sulphur Works area in the national park, although acquisition of the land proved contentious. Eventually, in 1952, the property was taken through condemnation proceedings and became part of Lassen Volcanic National Park.

Steam escapes from fumaroles on the site.

A closeup view of one of the geothermal features at Sulphur Works is shown below.

The forest in the area is made up of red fir and western white pine.

Bumpass Hell One of the major geothermal features in the park is Bumpass Hell, pictured below. The largest thermal area in the park, it features hot springs, boiling muddy pools, sulphur vents, and mud volcanoes. The water in the hot springs is extremely hot, ranging from temperatures of 125 to 196 degrees. At this location, molten volcanic rock lies a few miles beneath the surface.

This area is named after pioneer Kendall Vanhook Bumpass. Bumpass, a backwoods hunter, first saw the area in 1865, reporting sulphur vapors and boiling mud pots. Bumpass famously broke through the surface crust into boiling mud, coating and burning his leg, after cautioning those he was guiding into the area to show caution.

Seen in the picture below, there is a 1.4 mile Nature Trail which provides access for visitors to the geothermal features which exist in the basin. Lying at an altitude at 8200 feet, the basin has been created by the corrosion of solid rock by chemical effects of hot sulfuric acid.

- Next Page for Lassen Volcanic National Park -

  • All photographs ©Patrick Holleran, Shannon Digital Imaging, 1994-2012

  • Commercial use of the images contained in this document without express written consent is strictly prohibited.

  • Comments and other remarks can be sent via e-mail to parkvision@shannontech.com