The 'Iao Valley (pronounced ee-oww) was the site of the Battle of Kepaniwai or 'Battle of the Dammed Waters' in 1790 in which King Kamehameha I who unified Hawaii invaded Maui and defeated the son of Maui's king Kahekili II - who was on Oahu at the time - in a brtual three day long engagement.
Called the 'Battle of the Dammed Waters' because of all of the bodies stacked up in the river, it has also been referred to as the 'Battle of the Clawed Cliffs' due to the fact that Kamehameha was able to break what seemed to be an even draw with the use of two cannons to finally force the Maui people to the back of the valley and then - blasting the rock with cannon shot - sent the poor trapped souls clawing up the canyon walls for their lives.
Now maintained as a State Monument, the 'Iao Valley offers a paved 0.6 mile walk to a viewpoint of Kuka'emoku ('Iao Needle) which stands 1,200 feet above the valley floors (and pictured above.) There is also a wonderful botanical garden.
Entrance Fee: $5 per car
Hours: Open daily from 7:00 a.m. to 5:30 p.m. from Oct 1st - March 31st, and 7:00 a.m. to 6:00 p.m. from April 1st to Sept 30th