|Castro Valley, California|
|— CDP —|
Castro Valley Boulevard
Location of Castro Valley within Alameda County, California.
|- Mayor||N/A (Alameda County Board of Supervisors)|
|- Senate||Loni Hancock
Ellen Corbett (D)
|- Assembly||Mary Hayashi
Alberto Torrico (D)
|- U. S. Congress||Barbara Lee (D) (CA-09)|
|- Total||14.8 sq mi (38.2 km2)|
|- Land||14.4 sq mi (37.4 km2)|
|- Water||0.3 sq mi (0.8 km2)|
|Elevation||164 ft (50 m)|
|Population (2000 Census)|
|- Density||3,869/sq mi (1,493.8/km2)|
|Time zone||PST (UTC-8)|
|- Summer (DST)||PDT (UTC-7)|
|ZIP codes||94546, 94552|
|GNIS feature ID||1658237|
Castro Valley is a census-designated place (CDP) in Alameda County, California, United States. As of the 2000 census, it is the fifth most populous unincorporated area in California, and the twenty-third in the United States.
Castro Valley has a number of Eichler houses.
With the arrival of Europeans, Castro Valley was part of the land granted to Mission San Jose in 1797. The area Castro Valley now occupies was part of the extensive colony of New Spain in what was the state of Alta California.
Castro Valley is named after Don Guillermo Castro, who was a soldier in the Mexican army and a rancher. Castro Valley was part of the original 28,000 acre (110 km²) land grant given to Castro, called Rancho San Lorenzo. This land grant included Hayward, San Lorenzo, and Castro Valley, including Crow Canyon, Cull Canyon, and Palomares Canyons. Castro had a gambling habit and had to sell off portions of his land to pay gambling debts. The last of his holding was sold in a sheriff's sale in 1864 to Faxon Atherton for $400,000.
Atherton (after whom the city of Atherton is named) in turn began selling off his portion in smaller parcels. Two gentlemen named Cull (the namesake of Cull Canyon) and Luce bought some 2,400 acres (10 km²) and began running a steam-operated saw mill in Redwood Canyon. The Jensen brothers also bought land from Atherton in 1867.
During the 1940s and 1950s, Castro Valley was known for its chicken ranches. Later it developed into a bedroom community, where workers live and commute to their jobs in the surrounding communities.
Castro Valley is located at  Lake Chabot lies at the north of Castro Valley. Directly to the west is San Leandro. Hayward is to the south. To the east, the closest cities are San Ramon, Dublin and Pleasanton. The San Leandro Hills extend along the northeastern edge of the community.(37.703796, -122.079384).
The eastern hills of Castro Valley constitute the headwaters of the San Lorenzo Creek watershed and the origin of several creeks that flow into San Lorenzo Creek: Bolinas, Castro Valley, Chabot, Crow, Cull, Eden, Hollis, Kelly Canyon, Norris, and Palomares creeks
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.
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.
Castro Valley is an unincorporated community and thus is governed directly by the County of Alameda. To date, all efforts to incorporate Castro Valley have been voted down by its residents.
Castro Valley is served by the Castro Valley Unified School District. Overall, the district contains almost 9,000 students. The district includes the following public schools:
There is also a Roman Catholic school, called Our Lady of Grace (K-8), which is part of the Roman Catholic Diocese of Oakland. Redwood Christian Schools has two elementary schools in Castro Valley: Crossroads Christian Elementary and Redwood Christian Elementary. Castro Valley also holds a private elementary school and preschool called Camelot Elementary.
On 1 May 2003, the body of a young girl was found in a large green bag near the dumpster of a Carrows restaurant. After years of research, it was revealed that the girl was 16-year-old Yesenia Nungaray.