Chaos Crags is a cluster of young volcanic domes in northwestern Lassen Volcanic National Park, about two miles north of Lassen Peak. Formed beginning about eleven hundred years ago by vent-opening eruptions, pumice and ash, and thick rhyodacite lava, the crags are the park’s youngest lava domes and among the Lassen volcanic center’s most recent features. After six domes formed, one was later destroyed in a violent eruption, and about three hundred fifty years ago a massive slope collapse created the Chaos Jumbles and Manzanita Lake. With sharp, unglaciated surfaces and ongoing instability, the area remains both a major geologic landmark and an active hazard site under continued monitoring.