Wailuku is a census-designated place (CDP) in and county seat of Maui County, Hawaiʻi, United States. The population was 15,313 at the 2010 census.
Wailuku is located at 20°53′31″N 156°30′8″W / 20.89194°N 156.50222°W / 20.89194; -156.50222 (20.891923, -156.502177) between the CDPs of Waihee-Waiehu to the north, Kahului to the east, and Waikapu to the south.
The town is situated at 249 feet (76 m) above sea level, at the base of West Maui Volcano, known historically as Mauna Kahalawai and Hale Mahina, on the northern edge of the isthmus of East Maui (Haleakalā) and West Maui.
According to the United States Census Bureau, the CDP has a total area of 5.7 square miles (14.8 km), of which 5.3 square miles (13.8 km) is land and 0.42 square miles (1.1 km), or 7.16%, is water.
The three moku or districts of west Maui are Lāhaina, Kāʻanapali, and Wailuku. Wailuku is also known as Pūʻalikomohana, or Nā Wai ʻEhā which means the four waters. The four waters are the ahupuaʻa (smaller land division than district), which are Waikapū, Wailuku, Waiʻehu, and Waiheʻe.
As of the census of 2000, there were 12,296 people, 4,535 households, and 3,015 families residing in the CDP. The population density was 2,427.4 people per square mile (936.4/km²). There were 4,780 housing units at an average density of 943.6 per square mile (364.0/km²). The racial makeup of the CDP was 42.08% Asian, 26.28% from two or more races, 11.70% Pacific Islander, 8.16% White, 1.18% from other races, 0.36% Native American and 0.24% African American. Hispanic or Latino of any race were 7.75% of the population
There were 4,535 households out of which 29.1% had children under the age of 18 living with them, 48.4% were married couples living together, 12.7% had a female householder with no husband present, and 33.5% were non-families. 25.7% of all households were made up of individuals and 8.2% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.28.
In the CDP the population was spread out with 23.7% under the age of 18, 7.1% from 18 to 24, 30.3% from 25 to 44, 23.9% from 45 to 64, and 15.1% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 99.4 males. For every 100 females age 18 and over, there were 97.0 males.
The median income for a household in the CDP was $45,587, and the median income for a family was $51,441. Males had a median income of $33,429 versus $26,487 for females. The per capita income for the CDP was $20,503. About 8.1% of families and 11.2% of the population were below the poverty line, including 14.7% of those under age 18 and 3.8% of those age 65 or over.