The Iao Needle is a rock formation covered by greenery located on the Hawaiian Island of Maui inside the Iao Valley State Park. The rock formation is 1,200 feet high and is part of the West Maui Mountains, a dormant volcano. A historic battle took place here in 1790 lead by King Kamehameha. The Iao Needle was an ideal spot to observe the enemies movement and played a large role in Maui’s quest to unite all the Hawaiian islands under one rule.