Lassen Volcanic National Park, National park in Shasta County, California, US

Lassen Volcanic National Park is a national park in Shasta County in northeastern California, covering roughly 106,452 acres of volcanic landscape. The park includes Lassen Peak at 10,457 feet (3,187 meters) along with hot springs, clear mountain lakes, and multiple volcanic formations such as cinder cones and lava flows.

Theodore Roosevelt designated Lassen Peak and Cinder Cone as national monuments in 1907, after explorers and settlers opened the region during the 19th century. Between 1914 and 1917 the volcano erupted and sent ash across surrounding valleys, which led to the creation of the national park in 1916.

The peak was called San Jose, Mount Joseph or Mount Saint Joseph before prospector Grover K. Godfrey renamed it after meeting Peter Lassen in 1851. The Atsugewi, Yana and Maidu came in summer to hunt, fish and gather berries and nuts. The Kohm Yah-mah-nee Visitor Center carries the Mountain Maidu name for the peak.

The Kohm Yah-mah-nee Visitor Center offers geological exhibits and information for guests wanting to learn about the volcanic features of the area. In winter, heavy snowfall limits access to higher elevations, while lower areas remain open to visitors.

Lassen Volcanic National Park is one of the few areas in the world where all four types of volcanoes—plug dome, shield, cinder cone, and stratovolcano—are found together. The park's heat comes from the Gorda plate subducting beneath the North American plate off the Northern California coast, and the area still has boiling mud pots, fumaroles, and hot springs.