Lava Beds National Monument, located in Siskiyou and Modoc Counties, California, is the site of the largest concentration of lava tube caves in the United States. It was established as a United States National Monument on November 21, 1925.
The monument lies on the northeast flank of the Medicine Lake Volcano, the largest volcano (total area covered) in the Cascade Range. The region in and around the monument is unique because it lies on the junction of the Sierra-Klamath, Cascade, and Great Basin physiographic provinces. In addition, the monument is geologically outstanding because of its great variety of "textbook" volcanic formations; i.e., lava tube caves, fumaroles, cinder cones, spatter cones, maar volcanos, and lava flows.

Over 30 separate lava flows located in the park range in age from 2,000,000 years BP to 1,110 years BP. Some of the major Lava Flows within Lava Beds National Monument include: Callahan Flow, Schonchin Flow, Mammoth Crater Flow, Modoc Crater Flow, and Devils Homestead Flow. Schonchin Butte is an example of a cinder cone.

The high elevation, semi-arid desert environment of Lava Beds receives an average of 15 inches of annual precipitation. The climate is characterized by warm, dry summers and cold winters. The average annual high temperature is 60 °F and average annual low temperature is 35 °F. Temperature extremes range from 18 °F to 102 °F. Average annual snowfall is 44 inches.

Volcanic eruptions on the Medicine Lake shield volcano have created an incredibly rugged landscape punctuated by cinder cones, lava flows, spatter cones, lava tube caves and pit craters. During the Modoc War of 1872-1873, the Modoc Indians used these tortuous lava flows to their advantage. Under the leadership of Captain Jack, the Modocs took refuge in "Captain Jack's Stronghold," a natural lava fortress. From this base a group of 53 fighting men and their families held off US Army forces numbering up to ten times their strength for five months. Gen E. R. S. Canby was killed here by Captain Jack at a peace meeting on April 11, 1873.