ABSTRACT
LASSEN VOLCANIC PARK Lassen Volcanic National Park was added on August 9, 1916. Mount Lassen, in northern California, the only active volcano in continental United States, had been studied by J. S. Diller of the United States Geological Survey for more than thirty years. It was known at least as early as 1865, but only to a few local residents. It was covered into a national forest, and on May 6, 1907, President Theodore Roosevelt set aside as national monuments Cinder Cone, elevation 6,913 feet, and Lassen Peak, elevation 10,453 feet, both active more than a half century before but apparently dead or dormant. 1
