Kailua /kaɪˈluːə/ is a census-designated place (CDP) in Honolulu County, Hawaii, United States. It lies in the Koʻolaupoko District of the island of Oʻahu on the windward coast at Kailua Bay. It is in the judicial district and the ahupua’a named Ko’olaupoko. It is 12 miles (19 km) northeast of Honolulu – over Nu‘uanu Pali. The population was 38,635 at the 2010 census.
Kailua is located at 21°23′51″N 157°44′22″W / 21.39750°N 157.73944°W / 21.39750; -157.73944 (21.397370, −157.739515). Nearby towns include Kāneʻohe, Maunawili, and Waimānalo.
According to the United States Census Bureau, the CDP has a total area of 10.6 square miles (27.4 km). 7.8 square miles (20.1 km) of it is land, and 2.8 square miles (7.3 km) of it (26.62%) is water. A significant portion of this water area is Kawai Nui Marsh, the largest wetland in the Hawaiian Islands and a nominated Ramsar Convention site.
As of the census of 2000, there were 36,513 people, 12,229 households, and 9,318 families residing in the CDP. The population density was 5,495.8 people per square mile (2,123.2/km²). There were 12,780 housing units, at an average density of 1,923.6 per square mile (743.1/km²). The racial makeup of the CDP was 43.84% White, 0.76% Black or African American, 0.30% Native American, 21.11% Asian, 8.07% Pacific Islander, 0.93% from other races, and 24.99% from two or more races. Hispanic or Latino of any race were 6.10% of the population.
There were 12,229 households out of which 32.1% had children under the age of 18 living with them, 59.2% were married couples living together, 12.2% had a female householder with no husband present, and 23.8% were non-families. 16.6% of all households were made up of individuals, and 6.0% had someone living alone who was 65 years of age or older. The average household size was 2.98, and the average family size was 3.33.
In the CDP the population was spread out with 24.1% under the age of 18, 7.2% from 18 to 24, 28.6% from 25 to 44, 26.3% from 45 to 64, and 13.7% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 97.9 males. For every 100 females age 18 and over, there were 95.4 males.
The median income for a household in the CDP was $72,784, and the median income for a family was $79,118. Males had a median income of $46,789, versus $35,612 for females. The per capita income for the CDP was $29,299. About 3.3% of families and 5.4% of the population were below the poverty line, including 5.3% of those under the age of 18 and 1.5% of those 65 and older.