The Lassen volcanic center includes Brokeoff Volcano, Lassen's dacitic lava dome, and a number of small andesitic shield volcanoes found northeast of Lassen Peak. The Lassen dome field includes 30 dacitic lava domes such as Bumpass Mountain, Mount Helen, Ski Heil Peak, and Reading Peak; other major lava domes include Chaos Crags, Eagle Peak, Sunflower Flat, and Vulcans Castle. Nearby shield volcanoes include Prospect Peak and West Prospect Peak, and there are three cones close to Lassen Peak: Cinder Cone, Hat Mountain, and Raker Peak. The hydrothermal area inside the Lassen Peak volcanic center, with features located southeast and southwest of Lassen Peak, represents the largest geothermal area in the United States besides the one present at Yellowstone National Park.