Iao

Valley, Maui county, northwestern Maui Island, Hawaii, U.S., on the eastern slope of Puu Kukui Mountain. Formed by erosion of the caldera whose volcano created the island's western peninsula, the valley comprises a deep, narrow gorge 5 miles (8 km) long and flanked by heavily forested walls almost a mile in height. Iao Needle, a volcanic monolith 2,250 feet (686 m) high, soars nearly straight