Newberry Volcano is a vast active volcano in central Oregon and the largest in the Cascade Volcanic Arc, spreading across about 1,200 square miles with its lava fields. Formed about 600,000 years ago, it has erupted thousands of times and produced an unusual range of volcanic materials and landforms, including more than 400 vents, cinder cones, domes, and lava flows. A major eruption about 75,000 years ago created its present summit caldera, now holding Paulina Lake and East Lake. Named for John Strong Newberry after his 1855 exploration, it remains active today, monitored because nearby communities could be threatened by future eruptions and related hazards.