The Mono–Inyo Craters are a twenty-five-mile volcanic chain in eastern California stretching from Mono Lake past Mammoth Mountain, made up of domes, craters, cinder cones, explosion pits, fumaroles, and lava flows along a narrow fissure system. Volcanic activity began hundreds of thousands of years ago and continued into the recent past, with features such as the Mono Craters, Inyo Craters, Red Cones, Panum Crater, and the uplift of Paoha Island showing different stages of eruption and underground intrusion. The region also has a long human history, from Mono Paiute obsidian use to timbering, water diversion to Los Angeles, and later protection as a scenic and recreational landscape.