According to the U.S. Census Bureau, the county has a total area of 5,509 km² (2,127 mi²). 1,553 km² (600 mi²) of it is land and 3,955 km² (1,527 mi²) of it is water. The total area is 71.80% water. However, the majority of this area is the Pacific Ocean that surrounds the island.
As of the 2000 Census2, there were 876,156 people, 286,450 households, and 205,671 families residing in the county. The population density was 564/km² (1,461/mi²). There were 315,988 housing units at an average density of 203/km² (527/mi²). The racial makeup of the county was 21.28% White, 2.35% Black or African American, 0.25% Native American, 46.04% Asian, 8.87% Pacific Islander, 1.28% from other races, and 19.93% from two or more races. 6.70% of the population were Hispanic or Latino of any race.
There were 286,450 households out of which 31.80% had children under the age of 18 living with them, 54.50% were married couples living together, 12.30% had a female householder with no husband present, and 28.20% were non-families. 21.60% of all households were made up of individuals and 7.00% had someone living alone who was 65 years of age or older. The average household size was 2.95 and the average family size was 3.46.
In the county the population was spread out with 23.80% under the age of 18, 10.10% from 18 to 24, 30.60% from 25 to 44, 22.00% from 45 to 64, and 13.40% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 101.10 males. For every 100 females age 18 and over, there were 99.70 males.
Cities and towns on O'ahu