Castro Valley has a number of Eichler houses.
As of the census of 2000, there were 57,292 people, 21,606 households, and 15,016 families residing in the CDP. The population density was 3,971.6 people per square mile (1,533.0/km²). There were 22,003 housing units at an average density of 1,525.3/sq mi (588.7/km²). The racial makeup of the CDP was 70.84% White, 5.14% Black or African American, 0.59% Native American, 13.54% Asian, 0.44% Pacific Islander, 4.11% from other races, and 5.34% from two or more races. 12.19% of the population were Hispanic or Latino of any race.
There were 21,606 households out of which 32.3% had children under the age of 18 living with them, 54.0% were married couples living together, 11.0% had a female householder with no husband present, and 30.5% were non-families. 23.2% of all households were made up of individuals and 9.3% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 3.05.
In the CDP the population was spread out with 23.7% under the age of 18, 6.8% from 18 to 24, 29.8% from 25 to 44, 25.0% from 45 to 64, and 14.7% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 94.6 males. For every 100 females age 18 and over, there were 91.0 males.
The median income for a household in the CDP was $64,874, and the median income for a family was $73,060 (these figures had risen to $73,756 and $87,214 respectively as of a 2007 estimate). Males had a median income of $51,068 versus $38,907 for females. The per capita income for the CDP was $30,454. About 2.7% of families and 4.5% of the population were below the poverty line, including 4.3% of those under age 18 and 4.5% of those age 65 or over.
Interstate 580, which approaches from the east, makes a turn northward at Castro Valley. Interstate 238, which originates in Castro Valley, connects I-580 to Interstate 880. In addition to being served by those two freeways, Castro Valley is served with public transportation by bus system AC Transit, and rapid transit system BART with a station.