Kailua Ahupua‘a is the largest ahupua‘a of the Moku of Koʻolaupoko; the northern boundary of Kailua ahupua‘a, known traditionally as Pu‘u Pāpa‘a, or scorched hill, was given the name of Oneawa Hills in the 1970s. A stream runs through Oneawa ‘ili to the sea, providing a natural drainage for the Kawainui marsh. The Kawainui Canal was constructed in 1952 to provide flood control and stability for real estate development.
Oneawa was a famous fishery off the beach for awa (milkfish) and ʻōʻio (bonefish.) Awa are surface feeders that eat seaweed, while ʻōʻio are bottom feeders that forage in the sand, especially for crabs. The sea off Oneawa (Milkfish sand) – also the name of the ridge between Kāne’ohe and Kailua, as well as a land division – was “famous for the quality and quantities of the ʻōʻio, which are found in immense schools in the adjoining water; it was formerly a favorite residence of the Old Oahu chiefs”.