The Jornada del Muerto volcano and malpaís are located at the northern end of the desert's region and basin. The Jornada del Muerto Volcano is a shield volcano that erupted about 760,000 years ago, reaching an elevation of . The volcano's lava flow created the large Jornada del Muerto malpaís lava field, about , over 170 square miles (440 km2) in size. The eruption produced a slow and viscous a'a lava which leaves a very rough surface, making travel across it quite difficult.