Boulder Creek is located at GR1.(37.125, -122.125)
As of the censusGR2 of 2000, there were 4,081 people, 1,630 households, and 1,025 families residing in the CDP. The population density was 371.6/km² (963.3/mi²). There were 1,829 housing units at an average density of 166.6/km² (431.7/mi²). The racial makeup of the CDP was 90.25% White, 0.59% African American, 1.10% Native American, 1.72% Asian, 0.20% Pacific Islander, 2.18% from other races, and 3.97% from two or more races. Hispanic or Latino of any race were 5.68% of the population.
There were 1,630 households, of which 31.8% had children under the age of 18 living with them, 48.1% were married couples living together, 10.1% had a female householder with no husband present, and 37.1% were non-families. 25.6% of all households were made up of individuals and 4.2% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 3.02.
In the CDP the population was spread out with 23.6% under the age of 18, 7.9% from 18 to 24, 33.8% from 25 to 44, 28.7% from 45 to 64, and 6.0% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 101.1 males. For every 100 females age 18 and over, there were 101.6 males.
The median income for a household in the CDP was $60,455, and the median income for a family was $66,037. Males had a median income of $48,125 versus $40,197 for females. The per capita income for the CDP was $32,012. About 1.9% of families and 8.0% of the population were below the poverty line, including 0.9% of those under age 18 and 7.4% of those age 65 or over.
Many people who reside within Santa Cruz County near Boulder Creek (including Forest Park, Forest Springs, Big Basin, Wildwood, Redwood Grove, Riverside Grove, San Lorenzo Park and Bear Creek) consider themselves to be Boulder Creek residents; however they are not included in the Boulder Creek census data above. It is estimated that the number of people considering themselves residents of Boulder Creek could be two to three times as many as those who actually are.
Boulder Creek is also the gateway town to Big Basin Redwoods State Park, which is California's oldest State Park, founded in 1902.