Not much remains to be seen of this unique and still functional aqueduct, yet its archaeological significance is immeasurable. It's the only example of precontact cut and dressed stonework in Hawaii, said to be the work of the menehune (the little people), who allegedly completed it within one night for aliʻi (royalty).
To get here, follow Menehune Rd inland from Kaumualiʻi Hwy nearly 1.5 miles to the bridge along the Waimea River. Look for the interpretive signboard opposite.