Location and Geologic Setting

 

Location map of Lava Beds National Monument:
Northern California near the city of Tulelake.

The Lava Beds National Monument (LBNM) is situated in northeastern California and lies within both Siskiyou and Mondoc County. The park covers approximately 47,000 acres of land and was established as a United States National Monument in 1925 by President Calvin Coolidge. The park sits on a portion of the Medicine Lake shield volcano, which is considered a part of the Cascade Mountain Range. The Medicine Lake shield volcano is unique among other Cascade volcanoes in that it covers a large surface area. Because of the volcano's intermittent eruption patterns over the past 500,000 years, the park is home to many unique geologic features such as lava tube caves, cinder cones, spatter cones, craters, and fault scarps. The most recent flows from Medicine Lake resulted in what is now known as Glass Mountain, a mountain of obsidian and pumice that was created from an eruption less than 900 years ago. While Glass Mountain is not technically within the bounds of the Lava Beds National Monument, it is certainly a unique feature that is geologically tied to Lava Beds.

Welcome sign at Lava Beds National Monument