In 1969, eruptions from Kilauea's East Rift Zone began building a new lava shield, Mauna Ulu (Growing Mountain). By the time the flow stopped in 1974, it had covered 10,000 acres of park and added 200 acres of new coastal land. It also buried a 6-mile section of the original Chain of Craters Road in lava up to 300ft deep. Today the signed turnoff for Mauna Ulu is 3.5 miles down Chain of Craters Road.
The Puʻu Huluhulu Trail and its continuation, the more demanding Napau Crater Trail begin here.