The Hakalau Stream flows from the slopes of Mauna Kea, in the area of 19°48′55″N 155°21′55″W / 19.81528°N 155.36528°W / 19.81528; -155.36528 and flows into the Pacific Ocean.Hakalau was once a thriving, multiethnic sugarcane plantation town up until the early 1960s when the plantation originally called Hakalau Plantation Company began to decline. In 1963 it was merged into the Pepeʻekeo Sugar Company, in 1973 merged into the Mauna Kea Sugar Company, and the mill shut down in 1974.Small family farms now grow tropical fruits, taro, flowers, coffee, or cattle. Some historic sites remain from the plantation era. The privately owned sugar plantation managers home built in the early 20th century still exists, along with two warehouses built in 1920 and an old theater, operating as the Hakalau post office, postal code 96710. Located just below the ocean cliff where the Hakalau stream meets the bay, the old sugar mill ruins are still visible.