Which California national park is centered on the volcanic peak Lassen Peak?

The California national park centered on the volcanic peak Lassen Peak is Lassen Volcanic National Park.

Lassen Peak is the park’s dominant feature and the world’s largest plug dome volcano. It is also the southernmost volcano in the Cascade Range. The mountain formed when viscous dacite lava pushed upward and solidified near the summit rather than flowing easily away.

The park was created on August 9, 1916, after a series of eruptions at Lassen Peak from 1914 through 1917. A major eruption on May 22, 1915, sent an ash plume high above the mountain and produced mudflows and volcanic debris. Earlier, President Theodore Roosevelt had established Lassen Peak and Cinder Cone as separate national monuments in 1907.

Lassen Volcanic is broader than its namesake summit: it contains all four major volcano types—plug dome, shield, cinder cone, and stratovolcano—plus fumaroles, boiling mudpots, hot springs, lava fields, and remnants of the older Mount Tehama. It is therefore not simply a single-mountain park.