Trona Pinnacles is a protected geological area in the California Desert National Conservation Area near Trona, at the dry bed of Searles Lake. More than 500 tufa spires rise from dried mud across 3,800 acres of federally managed land, with forms ranging from narrow towers to ridges and low cones. They formed underwater during the Pleistocene as calcium-rich groundwater mixed with alkaline lake water in an ancient chain of inland lakes fed by Sierra Nevada runoff. Developed over roughly 10,000 to 100,000 years in distinct clusters tied to changing lake levels, the pinnacles preserve evidence of that vanished lake system while remaining a fragile and widely filmed desert landmark.