Geography
As of the census of 2000, there were 3,645 people, 1,274 households, and 983 families residing in the CDP. The population density was 140.0/km² (362.7/mi²). There were 1,311 housing units at an average density of 50.4/km² (130.5/mi²). The racial makeup of the CDP was 90.67% White, 0.47% African American, 1.78% Native American, 1.15% Asian, 0.11% Pacific Islander, 2.22% from other races, and 3.59% from two or more races. Hispanic or Latino of any race were 10.70% of the population.
There were 1,274 households out of which 37.3% had children under the age of 18 living with them, 63.9% were married couples living together, 8.2% had a female householder with no husband present, and 22.8% were non-families. 16.9% of all households were made up of individuals and 4.7% had someone living alone who was 65 years of age or older. The average household size was 2.86 and the average family size was 3.22.
In the CDP the population was spread out with 27.4% under the age of 18, 7.1% from 18 to 24, 29.8% from 25 to 44, 27.6% from 45 to 64, and 8.1% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 104.1 males. For every 100 females age 18 and over, there were 100.2 males.
The median income for a household in the CDP was $56,975, and the median income for a family was $60,913. Males had a median income of $41,058 versus $31,371 for females. The per capita income for the CDP was $23,914. About 5.1% of families and 4.8% of the population were below the poverty line, including 4.6% of those under age 18 and 3.6% of those age 65 or over.

History
Harbison Canyon, after its unfortunate encounters with wildfires, is best known among locals for the presence of a nudist resort, "Sun Island resort". Harbison Canyon is home to Old Ironsides Park, maintained by the County of San Diego Parks and Recreation. Kumeyaay Indian relics can be found near the stream that runs through the park and Canyon. The park also has a community center building where community and civic groups meet.