Wai'auia is located on the seaward side of Kawainui where the river that feeds Hamakua began in ancient times. This was a land for chiefs.

Wai'auia got its name because the ali'i who lived there had the water of the river "turned aside" into the waterpaths (or 'auwai) that their people made. Wai means "water." 'Auia means "to turn aside."

The river was utilized to make food plants grow in the many lo'i of Keahupua'anui near the wetlands of Hamakua. Farmers grew food crops such as taro, 'uala, etc. In days long ago, the sea was near to Wai'auia. Now the river flows under a road and the lo'i have been built over with the many buildings of Kailua town.