This report evaluates the volcano-related hazards, including regional mafic lava flows, silicic lava domes, pyroclastic flows, lahars, and volcanic ash, of the Lassen region, California, which is here defined as an area between the Pit River on the north and the southern limit of active Cascade volcanism, approximately 5 to 10 km south of the southern boundary of Lassen Volcanic National Park. Most active volcanism occurs in a zone about 40 km wide between Viola on the west and the eastern boundary of Caribou Wilderness Area, but sparser volcanism in the west extends the width of this zone to about 75 km. All vents and deposits known or estimated to be less than 100,000 years are identified and considered in establishing the hazard zones.