Waialua () is a census-designated place and North Shore community in the Waialua District on the island of Oahu, City & County of Honolulu, Hawaii, United States. As of the 2020 census, the CDP had a population of 4,062. Waialua was one of the six original districts of ancient Hawaii on the island, known as moku. Waialua is a former (sugar) mill town and residential area, quite different in its quiet ambiance from nearby Haleiwa, which is more commercial and tourist oriented. The Waialua Sugar Mill is the center of this town and the historical base of its plantation history. The U.S. postal code for Waialua is 96791. Geography Waialua is located at 21°34'31" North, 158°7'46" West (21.575300, -158.129457), southwest of Haleiwa, reached on Waialua Beach Road (State Rte. 82) or Kaukonahua Road (State Rte. 830). Kaukonahua Road turns eastward and, as State Rte. 803 then 801 runs up into the central plateau of Oahu to Wahiawā or (as 803) to Schofield Barracks. Farrington Highway (State Rte. 930) runs westward to Mokulēia. According to the United States Census Bureau, the CDP has a total area of , of which is land and is water. The total area is 8.30% water. Demographics As of the census of 2000, there were 3,761 people, 1,128 households, and 882 families residing in the CDP. The population density was . There were 1,219 housing units at an average density of . The racial makeup of the CDP was 15.34% White, 0.37% Black or African American, 0.05% Native American, 51.85% Asian, 3.96% Pacific Islander, 1.04% from other races, and 27.39% from two or more races. 6.54% of the population were Hispanic or Latino of any race. There were 1,128 households, out of which 29.3% had children under the age of 18 living with them, 55.4% were married couples living together, 14.5% had a female householder with no husband present, and 21.8% were non-families. 17.5% of all households were made up of individuals, and 8.3% had someone living alone who was 65 years of age or older. The average household size was 3.31 and the average family size was 3.71. In the CDP the population was spread out, with 23.9% under the age of 18, 7.7% from 18 to 24, 26.4% from 25 to 44, 23.1% from 45 to 64, and 18.9% who were 65 years of age or older. The median age was 39 years. For