The U.S. postal code for Kahuku is 96731.
Kahuku is located at 21°40'49" North, 157°57'1" West (21.680333, -157.950141)1. This community is located northwest from Lā'ie and east from Kuilima and Kawela Bay along Kamehameha Highway (State Rte. 83).
According to the United States Census Bureau, the town has a total area of 5.9 km² (2.3 mi²). 2.5 km² (1.0 mi²) of it is land and 3.4 km² (1.3 mi²) of it is water. The total area is 57.46% water, although all of this water is the Pacific Ocean lying off the coast included in the census tract.
As of the census of 2000, there were 2,097 people, 509 households, and 401 families residing in the town. The population density was 834.7/km² (2,150.9/mi²). There were 518 housing units at an average density of 206.2/km² (531.3/mi²). The racial makeup of the town was 11.06% White, 0.29% African American, 0.14% Native American, 26.85% Asian, 27.28% Pacific Islander, 1.05% from other races, and 33.33% from two or more races. 8.63% of the population were Hispanic or Latino of any race.
There were 509 households out of which 43.2% have children under the age of 18 living with them, 59.3% are married couples living together, 14.3% have a female householder with no husband present, and 21.2% are non-families. 19.8% of all households are made up of individuals and 11.0% have someone living alone who is 65 years of age or older. The average household size is 3.96 and the average family size is 4.63.
In the town the population is spread out with 35.4% under the age of 18, 10.7% from 18 to 24, 23.3% from 25 to 44, 17.8% from 45 to 64, and 12.7% who are 65 years of age or older. The median age is 28 years. For every 100 females there are 101.2 males. For every 100 females age 18 and over, there are 96.9 males.
The median income for a household in the town is $39,135, and the median income for a family is $47,045. Males have a median income of $29,934 versus $22,366 for females. The per capita income for the town is $12,340. 14.6% of the population and 11.8% of families are below the poverty line. Out of the total people living in poverty, 17.4% are under the age of 18 and 17.7% are 65 or older.