View mauka from the Maunawili Demonstration Trail
Maunawili Valley extends behind the prominent windward peak known as Olomana. The residential developments extend only part way back into the valley, which is quite large and fairly wet, supporting limited agriculture (mostly banana growing) behind the housing. Water from the numerous streams is diverted by a ditch to much drier Waimanalo to support agricultural activities there.
A golf course and agricultural research station (HSPA) are located in the valley. An attraction of increasing popularity is the Maunawili Demonstration Trail, a state-maintained trail that traverses the breadth of upper Maunawili Valley from the Pali Highway to Waimanalo. A connecting side trail (Maunawili Falls Trail) is accessible from the neighborhood in upper Maunawili.
The U.S. postal code for Maunawili is the same as for Kailua: 96734
Maunawili is located at 21°22'36" North, 157°45'37" West (21.376650, -157.760166)1. The nearest town to Maunawili is Kailua.
As of the census of 2000, there were 4,869 people, 1,458 households, and 1,224 families residing in the town. The population density was 540.2/km² (1,399.0/mi²). There are 1,491 housing units at an average density of 165.4/km² (428.4/mi²). The racial makeup of the town was 36.62% White, 0.55% African American, 0.08% Native American, 28.47% Asian, 8.79% Pacific Islander, 0.55% from other races, and 24.93% from two or more races. 5.79% of the population were Hispanic or Latino of any race.
There were 1,458 households out of which 31.7% had children under the age of 18 living with them, 68.7% were married couples living together, 11.1% had a female householder with no husband present, and 16.0% were non-families. 11.1% of all households were made up of individuals and 5.8% had someone living alone who is 65 years of age or older. The average household size was 3.10 and the average family size 3.31.
In the town the population was spread out with 23.0% under the age of 18, 6.1% from 18 to 24, 27.7% from 25 to 44, 26.9% from 45 to 64, and 16.2% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 89.2 males. For every 100 females age 18 and over, there were just 83.6 males.
The median income for a household in the town was $82,148, and the median income for a family was $84,294. Males had a median income of $51,078 versus $36,324 for females. The per capita income for the town was $30,551. 2.5% of the population and 1.5% of families were below the poverty line. Out of the total people living in poverty, 3.6% were under the age of 18 and 2.3% were 65 or older.